Tunnel Warfare in the Gaza Strip

Gaza's underground infrastructure represents a decades-long project that transformed a territory roughly 40 kilometers from north to south into a layered subterranean military environment.[5][4] Family-run smuggling passages beneath divided Rafah progressively developed into a network supporting movement, combat, concealment, logistics, and command. Gaza's layered soils of sand mixed with silt and clay can be stable enough in places for hand excavation, and tunnels have been built horizontally, vertically, or at an incline according to their purpose.[2][5]

Analysts distinguish three broad categories. Smuggling tunnels beneath the Rafah corridor carried goods, weapons, cash, and people between Gaza and Egypt. Attack tunnels directed toward Israel allowed armed squads to emerge inside Israeli territory for raids, killings, or abductions. Internal tunnels protected commanders, terrorists, and weapons; enabled battlefield movement and communications; concealed rocket infrastructure; and provided positions from which Hamas could engage Israeli forces at close range.[6][7] The categories sometimes overlapped as Hamas's capabilities expanded.

The network's significance lies in both its military utility and the strategic problems it created for Israel. Underground assets were difficult to locate through aerial surveillance, hostages could be dispersed within the system, and clearing tunnels required dangerous and resource-intensive engineering operations.[3][8] Tunnel destruction became a central objective of Israel's 2014 ground campaign and remained a major focus in the 2021 and post-October 7 wars.[9][10]

Militant tunnel-digging in Gaza dates to at least 1967, and Hamas later drew on this local tradition and on Hezbollah's tunneling experience along the Israel-Lebanon border.[1] A separate strand of the history began in 1982, when the Egypt-Israel peace arrangements divided Rafah between Gaza and Egypt. Residents dug passages beneath the border to smuggle goods and reconnect separated families; these early Rafah tunnels were not initially associated with terrorism.[2]

Smuggling activity increased after the Oslo-era Israeli withdrawal from much of Gaza in 1994, while arms smuggling intensified around 2000.[2][5] During the Second Intifada, Hamas used tunnels opposite Israeli positions along the Philadelphi Route to place explosive charges beside those positions.[11] In June 2004, a booby-trapped tunnel at the Orhan outpost killed one Israeli soldier and wounded five; in December 2004, a cross-border tunnel attack at a Rafah outpost killed five soldiers and wounded six.[12]

Israel's official account of the 2014 conflict dates the digging of tunnels for direct military activity against Israel to 2001 and describes them as becoming longer, deeper, more stable, and more secure over time.[10] The Gaza-Sinai smuggling network expanded after Israel's 2005 disengagement, with Hamas promoting its growth. Under the closure regime then in effect, the tunnels served as both an economic channel and a means of supplying terrorist organizations, and many openings were reportedly located inside buildings in or near Rafah.[13]

By 2007, when Hamas seized control of Gaza, tunnels led to rocket and mortar positions, smuggling routes, logistics centers, and command-and-control headquarters.[2] Israeli restrictions on goods following the takeover coincided with further expansion of the Rafah tunnel industry and the development of underground rocket and military infrastructure inside Gaza.[5]

The tunnels beneath the Rafah border corridor constituted an elaborate smuggling infrastructure. They ran between houses on opposite sides of the Egypt-Gaza border and were operated primarily by Gaza clans motivated by profit. Authorities reported tunnels as deep as 98 feet, apparently intended to avoid sonar detection; better-equipped passages had air ducts, electricity, lighting, and rails and wagons for hauling heavy goods. When tunnel mouths were sealed, intact midsections could be reconnected by digging new shafts.[14]

Hamas and other organizations rented access to tunnels for a few thousand dollars per night or longer to move weapons and other material.[14] Goods included fuel, food, medicine, building materials, weapons, ammunition, rocket components, and cash. Terrorists also reportedly traveled through the network to and from Iran and Lebanon for training and assistance.[13] Contemporary estimates in 2010 placed the number of tunnels at more than 1,000 and the workforce at approximately 7,000, with some tunnels equipped with electricity, ventilation, intercoms, and rail systems.[13]

Israeli airstrikes during Operation Cast Lead in 2008-2009 rendered more than 100 tunnels inoperative, but many were restored within weeks because the damage was concentrated at their entrances rather than their midsections.[13] Egyptian operations later closed much of the smuggling system, while Hamas continued developing a separate internal network inside Gaza.[15] The IDF has also stated that Hamas used tunnels beneath the Egypt-Gaza border to smuggle weapons and ammunition before the October 7, 2023 attack.[16]

The most direct threat to Israeli territory came from attack tunnels dug beneath the border. They were engineered for infiltration rather than commerce: assault squads could emerge from concealed shafts inside Israel, attack soldiers or civilians, abduct captives, and withdraw into Gaza.[11][10]

A major tunnel attack occurred on June 25, 2006, when a joint Hamas and Jaish al-Islam unit entered Israel near the Kerem Shalom crossing through an opening approximately 100 meters inside Israeli territory. The attack killed an officer and a soldier and led to the capture of Israeli soldier Gilad Shalit.[11] Shalit was held for five years and released in 2011 in exchange for 1,027 Palestinian prisoners held in Israel.[1]

From 2009 onward, Hamas developed strategic offensive tunnels beneath the 1949 armistice line, digging about 35, some extending hundreds of meters into Israel.[2] Some tunnels reported during Operation Protective Edge extended as far as 2.4 kilometers into Israeli territory.[11] They could have multiple entrance and exit shafts, divided main routes, and parallel passages, complicating efforts to map and destroy them.[12] One estimate placed the construction time for a tunnel at about three months and the cost at approximately $100,000; openings could be concealed in houses, greenhouses, and other structures.[12] Excavated soil was sometimes hidden inside hangars and greenhouses to avoid detection in aerial photographs.[17]

Equipment found in offensive tunnels included plastic handcuffs, anesthetics, and, in one case, three motorcycles apparently intended to facilitate movement inside Israel.[7] Prime Minister Benjamin Netanyahu described the system as a strategic network built for large-scale terrorist attacks and abductions and equipped with fortifications, electricity, and cables.[18]

Operation Protective Edge brought tunnel warfare to the center of Israeli public and military attention. On July 17, 2014, thirteen Hamas terrorists emerged from a cross-border tunnel near Kibbutz Sufa. The attempted attack was foiled, and Israel subsequently began a limited ground operation intended to locate and neutralize additional cross-border tunnels.[12][10]

Two overlapping systems shaped the fighting. Internal defensive and communications tunnels protected commanders, forces, weapons, and ammunition; supported communication, movement, and rocket operations; and provided protected fighting positions. Offensive tunnels allowed assault squads to cross the border undetected and attack targets inside Israel.[6]

The IDF discovered 32 offensive tunnels, 14 of which reportedly reached Israel, while two more had exits within 500 meters of the border.[6] A contemporaneous field report counted 40 tunnels found since the ground operation began as of July 30, apparently using a broader category.[17] Israel's official report states that by August 5 the IDF had located and destroyed 32 cross-border assault tunnels, after which ground troops withdrew from Gaza.[10]

Hamas conducted six tunnel-based infiltration operations during the fighting, four involving direct clashes with Israeli forces. Eleven Israeli soldiers were killed in those clashes.[6] At Nahal Oz, infiltrators killed five soldiers in an apparent attempted abduction operation.[6] Near Kibbutz Nir-Am, two groups entered Israel in an apparent planned attack, and at least fifteen terrorists were reported killed after large IDF forces intervened.[18] On August 1, terrorists killed three Israeli soldiers near Rafah and escaped through a tunnel with the body of Lt. Hadar Goldin.[12]

One tunnel exit inside Israel was found in a kibbutz dining hall. Many tunnels had concrete-lined walls and ceilings and electrical wiring, and the IDF attributed an estimated construction cost of approximately $3 million to each tunnel.[19] The ADL reported at least 32 tunnels and 60 passageways discovered during the fighting, with entrances hidden beneath homes, clinics, hospitals, and mosques and some booby-trapped.[19]

Ground combat inside Gaza was also shaped by defensive tunnels. Israeli forces encountered booby-trapped entrances, fought for access, and then undertook engineering work to trace and demolish the passages.[6] Engineers faced collapse, bombs, booby traps, and ambushes; one concrete-lined tunnel required ten days of work and had three branches.[17] Israel generally preferred not to enter tunnels because the attacking force had no inherent advantage in underground close combat. Methods included aerial attacks on shafts, water injection, and liquid explosives, although bombing a shaft could make the tunnel harder to locate by sealing its entrance.[12]

Israel's State Comptroller later found that the IDF had completely destroyed or neutralized only half of the tunnels it had designated as requiring treatment. That measure differed from the government's total for tunnels located and destroyed during the campaign.[20]

After the 2014 war, Hamas built a more extensive internal network known to Israel as the "Metro." A 2021 account estimated it at about 100 kilometers beneath much of the Gaza Strip, with passageways for movement, spaces for sleeping, eating, and showering, and areas for launching rockets. Hamas battalions were assigned sections of the network and trained inside them.[21] The tunnels were dug using hand tools and jackhammers, while Hamas concentrated command-and-control systems, production, communications, and logistics underground.[22][21]

During Operation Guardian of the Walls in May 2021, the IDF launched a large attack on the Metro under the code name "Lightning Strike." In one phase, 160 fighter jets dropped 500 bombs over 23 minutes while attempting to strike tunnel sections without collapsing entire neighborhoods above them.[21] The IDF reported striking 100 kilometers of tunnels during the campaign.[23] Later assessments concluded that the attacks did not permanently prevent Hamas from using the network and that damaged sections may have been repaired.[24] A 2025 INSS analysis characterized the operation as having proved "far less effective than initially celebrated."[9] Hamas leader Yahya Sinwar subsequently claimed that the network exceeded 300 miles and that Israel had destroyed only about one-fifth of it; these were unverified Hamas claims.[16]

Hamas continued construction after 2021. INSS estimated that the underground network measured 500-600 kilometers at the start of the October 7, 2023 war and connected military installations, headquarters, and facilities through thousands of shafts.[9] Tunnels served as shelters, warehouses, missile-production workshops, rocket-launch infrastructure, and bases for ground attacks. Small units emerged from concealed shafts in built-up or ruined areas to set ambushes, fire RPGs, or place explosive devices before withdrawing underground.[9]

Quantifying Gaza's tunnel network has proved difficult, and all published totals are attributed estimates rather than independently verified measurements. Hamas claimed in 2021 that the network comprised 1,300 tunnels extending about 500 kilometers.[23] Sinwar separately claimed a length of more than 300 miles.[16] Early-2024 Israeli assessments placed the network at 350-450 miles, compared with an earlier estimate of about 250 miles, and counted approximately 5,700 shafts.[25] A January 2024 INSS article relayed an IDF assessment of more than 700 kilometers and more than 5,700 shafts.[3] Ynet reported that the IDF's estimate rose from about 500 kilometers to at least 750 kilometers and possibly more than 1,000 after intelligence was extracted from Hamas documents.[15] A New York Times estimate relayed by Globes gave a range of 560-720 kilometers and said the system's scale and construction quality had astonished Israeli and American officials.[4]

Geologist Joel Roskin distinguished three depth bands. Shallow tunnels at about ten meters were associated with ground-accessible activity and rocket-launch shafts. Intermediate tunnels at 20-30 meters were described as containing ammunition, logistics equipment, and fighters. Deep tunnels reaching 75 meters were described as containing headquarters and sensitive facilities. Roskin assessed that Hamas leaders and Israeli hostages might be held at the deepest level, but this was an assessment rather than a verified location.[26] He also noted that groundwater lies at approximately that depth and might be exploited during a siege.[26]

The network ranged from narrow passages to tunnels large enough for motorcycles and small vehicles.[15] Larger routes could connect to observation systems and command rooms and contain rooms, utilities, and ventilation. Reports described a road-like system of main routes, bypasses, sea passages, explosive charges, doors, and other booby traps. Estimated excavation costs ranged from $200 to $300 per meter, with one estimate placing the overall cost at about $150 million.[23] Generators, electricity, food, and equipment were installed underground, while ventilation and air supply remained potential vulnerabilities. Zigzag layouts could disrupt communications, and stairs or slopes could hinder robots.[26]

Gaza's layered geology of sand, silt, and clay can permit excavation along a softer layer beneath a firmer roof, but accurate detection and destruction require detailed knowledge of local ground conditions.[5] Entrances were frequently concealed in residential structures. An INSS analysis relaying IDF data said shafts had been located under or near "almost every school, mosque, and hospital" within the network's coverage area; the claim was an attributed wartime assessment without an independently stated counting method.[3]

Tunnel infrastructure reportedly supported preparations for the October 7, 2023 Hamas terrorist attack, although available accounts did not indicate that the attackers used tunnels to cross into Israel. The IDF stated that Hamas had used tunnels beneath the Egypt-Gaza border to smuggle weapons and ammunition before the attack.[16] Hamas also reportedly used landlines installed underground to plan the operation, reducing exposure to cellular interception.[16] Footage released on October 14 showed terrorists emerging from tunnels, simulating an attack on Israeli tanks, and returning underground.[16]

Once Israel began its ground campaign, the tunnels became a central operational challenge. The IDF announced the destruction of about 100 tunnels by November 2, 2023, and 130 shafts by November 8.[25] By November 14, Israeli forces had found at least 500 shafts.[24] The network protected Hamas leaders and command systems, supported movement and rocket launches, and concealed hostages taken on October 7.[3]

On December 17, 2023, Israeli forces reported finding a tunnel entrance about 1,300 feet from the Erez crossing. The tunnel was described as more than 2.5 miles long, over 160 feet deep, and large enough for vehicles.[25] In 2024, the IDF reported uncovering a network more than ten kilometers long that passed beneath the Turkish-Palestinian Friendship Hospital and a nearby university and reached Gaza City's Zeitoun neighborhood. According to the IDF, troops found living quarters, bathrooms, and weapons depots before major sections were destroyed.[27]

During a September 2024 operation against the Rafah Brigade, the IDF reported destroying 203 tunnels covering eight miles, including nine that crossed into Egypt. It said those cross-border tunnels had previously been blocked by Hamas or Egyptian authorities.[25] After eighteen months of fighting, the IDF assessed that about 25 percent of the overall network had been destroyed, reflecting the technical difficulty of demolishing deep infrastructure and the risks to civilians and hostages.[28] Estimates of the total network continued to change as Israeli forces gathered documents and computers associated with tunnel construction.[25][15]

Tunnel warfare served Hamas as both a tactical and a strategic instrument, compensating for its inability to contest Israeli air superiority or operate openly on the surface. Underground systems allowed a less-equipped force to preserve combat power, achieve surprise, and draw an adversary into close-quarters engagements.[11]

Offensively, attack tunnels enabled assault squads to penetrate Israeli border defenses and emerge inside Israel to attack or abduct soldiers and civilians.[6][11] Underground rocket infrastructure provided a further offensive function: an opening could be exposed briefly for a launch and then closed, making the position difficult to detect and attack in real time.[11]

Defensively, internal tunnels concealed infrastructure, forces, ammunition, and leaders from air attack.[1][7] Commanders and terrorists could move between positions without exposure to overhead surveillance, while small units emerged from shafts to ambush infantry and armored forces before withdrawing underground.[9] The IDF's 2014 experience suggested that Israel won most close-combat actions, but Hamas still inflicted casualties and forced extensive engineering work.[6]

The network was also used to hold hostages taken on October 7. Dispersing captives underground complicated efforts to locate or rescue them, while attacks intended to destroy tunnels risked killing or injuring hostages inside and civilians above or nearby.[8] These risks remained a major constraint on Israeli operations.

A National Library of Israel catalog record identifies a restricted video excerpt from an interview with Hamas official Mousa Abu Marzouk under the title "The Tunnels in Gaza Were Built to Protect Hamas Fighters, Not Civilians." The catalog description says the excerpt addresses why Hamas built tunnels for its personnel but not for Gazan civilians, but the archive page provides no transcript and does not establish the interview's full context.[29]

Ayish and Fox argue that as combat inside the tunnels intensified, the IDF began treating the subterranean infrastructure as an interconnected network rather than a collection of isolated shafts. They describe a shift from concentrating on entrances toward simultaneous above-ground and underground operations, including entering and fighting within the system.[22]

Locating tunnels under construction, completed, or dormant posed a persistent technical challenge. Aerial surveillance could not reveal underground routes, and cellular reception was lost below ground, limiting intelligence options.[21] Israel relied partly on human sources and, during the post-October 7 war, on documents, interrogations, and computers captured during ground operations.[21][15]

Methods for detecting active digging included underground microphones, or geophones, intended to pick up construction noise. Techniques explored for locating completed tunnels included ground-penetrating radar, sound waves, vibration measurements, optical-fiber sensors, infrared measurements, and microgravity analysis. Background noise, soil strata, terrain, weather, and humidity could all affect the results, and many methods remained at an early stage during the 2014 war.[12]

After 2014, Israel pursued three linked efforts: intelligence mapping, real-time detection systems, and improved means of attack and demolition.[21] In October 2020, new underground sensors detected a tunnel running from Khan Younis toward Kibbutz Kissufim that the U.S. State Department report described as two kilometers long and 74 meters deep.[30] In April 2016, a sensor system developed through cooperation among the Defense Ministry, the Geophysical Institute of Israel, Elbit Systems, and a startup detected a tunnel about 30 meters deep extending several dozen meters into Israel.[31]

Israel also completed a 40-mile above- and below-ground border barrier in 2021, equipped with cameras, radar, and sensors and intended to prevent tunnel incursions.[16] The barrier did not prevent the above-ground October 7, 2023 attack.[9] Congress appropriated $320 million in Department of Defense funding for fiscal years 2016-2023 for U.S.-Israel cooperation on detecting, mapping, and neutralizing tunnels, while Israel reportedly spent billions of dollars on sensors and barrier construction.[8]

Once a tunnel was located, Israeli procedures generally involved isolating the area, searching for additional shafts and branches, and using engineering forces to demolish the structure. Methods included aerial attacks, water injection, liquid explosives, and gel-like explosives pumped through pipes.[12][24] An Israeli officer said several hundred meters of tunnel could require tons of explosive material.[24] In January 2024, the IDF confirmed that it was injecting seawater into selected tunnels in "Operation Atlantis." It said local soil and water conditions were assessed first to reduce the risk to groundwater, while walls and barriers sometimes slowed or stopped the water and the method's effectiveness remained uncertain.[32]

The IDF expanded tunnel-warfare instruction and built specialized training facilities after 2014, while its Yahalom engineering unit and regular combat formations received underground-combat training.[33][24] During the later war, the IDF categorized targets as tactical tunnels connecting buildings, operational tunnels linking units, and strategic tunnels that included cross-border smuggling routes. Drones, robots, and camera-equipped dogs were used for reconnaissance but initially had limited success in the complex environment.[28]

Gaza's tunnel network became a major example of asymmetric military engineering. Estimates placed excavation costs at about $150 million, while the earlier Rafah industry alone was reported to employ thousands of workers.[13][23] The network allowed Hamas to conceal forces and infrastructure, preserve some combat capacity under air attack, and force Israel into dangerous ground and engineering operations.[6][11]

The challenge produced significant changes in Israeli doctrine, technology, and training. The IDF developed new sensor systems, engineering procedures, specialized units, and underground-combat methods. The United States and Israel established a multi-year counter-tunnel cooperation program, while analysts drew broader lessons from the IDF's shift toward simultaneous above-ground and underground operations.[8][22]

For Israeli border communities, attack tunnels produced psychological insecurity beyond their measurable battlefield effect. The discovery of an exit inside a kibbutz dining hall demonstrated that terrorists could potentially emerge within a civilian community.[19] Netanyahu described the tunnels as a strategic network intended for large attacks and abductions.[18]

The network also shaped the humanitarian and legal dimensions of the conflict. The ADL reported entrances beneath homes, clinics, hospitals, and mosques, while Israel's official 2014 report alleged that Hamas and other terrorist organizations concealed military infrastructure within civilian areas.[19][10] Military operations around such sites became politically and legally contentious, and the possible presence of hostages underground further constrained Israeli options. After eighteen months of fighting, the IDF assessed that only about 25 percent of the network had been destroyed, while a 2025 INSS analysis concluded that Israel remained far from clearing the system.[9][28]

Quantitative claims about Gaza's tunnels—including their total length, number of shafts, depth, cost, and the proportion destroyed—are estimates rather than systematic independent measurements. Hamas's claim of 1,300 tunnels extending about 500 kilometers and Sinwar's claim of more than 300 miles were self-reported figures without external verification.[16][23] Israeli military estimates also changed substantially during the 2023-25 war as captured documents and other intelligence expanded the IDF's understanding of the network.[25][15]

Different campaigns also used different measures. Israel's official account reported 32 cross-border assault tunnels located and destroyed in 2014.[10] The IDF reported striking 100 kilometers of tunnels in 2021, while Sinwar claimed that only about one-fifth of the system had been destroyed.[16][23] In 2024, the IDF reported destroying 203 tunnels covering eight miles during one operation in Rafah.[25] These figures describe different categories and cannot be directly compared.

The State Comptroller's post-2014 finding that only half the tunnels designated for treatment had been completely destroyed or neutralized differed from the government's count of tunnels located and destroyed, illustrating the effect of using different metrics.[20]

Claims about tunnel access beneath civilian infrastructure remain politically and legally contested. Israeli sources have reported or alleged entrances and military infrastructure in homes, hospitals, clinics, mosques, schools, and other civilian locations.[19][10] Such claims should be read as attributed wartime findings rather than as universally accepted independent determinations.