The mysterious tunnels of Gaza, which have been dug by Gaza’s militias for close to 40 years, are often hidden beneath buildings, vegetation, and other terrain, posing a threat of urban warfare.
The risks of urban warfare and Hamas’s tunnel systems have forced Israel to postpone its highly anticipated ground assault on Gaza, which could have seriously damaged the prestige of the Israel Defense Force. How big are the tunnel networks beneath Gaza?
Over the past week, prominent retired US officials have surfaced to caution Israel against initiating a big ground offensive in Gaza.
“This is going to be a very, very tough fight,” retired former US Iraq and Afghanistan commander David Petraeus predicted in an interview with US media over the weekend. “There are tunnels; there will be rooms that will have improvised explosive devices. You have to clear every building, every floor, every room, every basement, every tunnel. Civilian losses are inevitable, and tough Israeli losses lie ahead as well,” Petraeus stressed.
President Biden concurred with the commander’s thoughts when he cautioned Tel Aviv on Wednesday not to make the same “mistakes” that America did in the wake of the 9/11 terrorist attacks.
“Justice must be done. But I caution this: While you feel that rage, don’t be consumed by it. After 9/11 we were enraged in the United States. While we sought justice and got justice, we also made mistakes,” Biden said, presumably referring to the US wars of unprovoked aggression in Afghanistan and Iraq in 2001 and 2003, and the US Seal Team Six assassination of alleged 9/11 mastermind Osama bin Laden in Pakistan in 2011.
Despite boastful promises by senior Israeli officials to wipe Hamas “off the face of the Earth” and an IDF deadline that expired last Saturday ordering over a million Palestinian civilians to leave the northern half of the Strip, Western and Israeli media have offered a variety of potential explanations for why the IDF hasn’t yet launched a ground invasion of Gaza. Concerns for the Israeli hostages held by militants, political appeals to allies alarmed by widespread civilian casualties, and worries by Israeli intelligence that Hezbollah in Lebanon might open a second front in the north the moment Israeli troops enter Gaza are a few of the potential explanations mentioned.
Tunnel Vision
IDF commanders are weary of the challenges they would inevitably face in ensuring battlefield superiority against the roughly 30,000 Hamas fighters in Gaza’s dense urban environment, much of which has already been reduced to piles of rubble ideal for ambushes and snipers’ nests as a result of Israeli airstrikes. This is a significant factor that may help explain Israeli reluctance about a ground-based operation inside Gaza.
Defenders typically hold the upper hand in urban conflict, as the Modern War Institute at West Point noted in a 2021 analysis.
“Today,” the paper stressed, “the advantages provided to a weaker force to occupy urban terrain are great. A weaker enemy can use the physical terrain for concealment and cover both to fight from (e.g. using heavy-clad buildings as de facto military-grade defensive structures) and to maneuver (e.g. through buildings or underground in civilian infrastructure and prepared tunnels). Defending forces can also hide among the protected populations and structures outlined by the laws of armed conflict. In short, they can reduce the effectiveness of a substantial portion of present-day military technologies and tactics.”
Put another way, urban environments threaten to turn into a great equalizer between the assault rifle, grenade, IED and anti-tank-gun-wielding Hamas fighters, and the technologically sophisticated, heavy armor, air and artillery supported Israeli army, with defenders not only able to see incoming attackers, but survive airstrikes using tunnels and pre-made holes in walls of buildings to live to fight another day. And that’s on top of their home turf advantage.
In the case of Hamas, tunneling has been a common tactic used by the militants to smuggle supplies and equipment across the heavily guarded border encircling Gaza for decades, and it is believed to have advanced to the point where it is now possible to construct entire underground networks to quickly move and evacuate fighters and equipment, run underground command posts, and even operate workshops for the manufacture of weapons.
Ismail Haniyeh, the head of the Hamas Political Bureau, bragged in 2018 that the Hamas tunnel network in Gaza had grown to be twice as large as the Cu Chi tunnels the Viet Cong excavated beneath Saigon during the US War in Vietnam. Hamas’s tunneling initiatives through the Gaza Strip have been dramatically revealed in detail maps based on IDF data. Israeli forces alone found about 100 km worth of underground tunnels during the 2014 Gaza War. Hamas revealed that it had constructed tunnels with a combined length of 500 km in 2021.
The Israeli military’s sophisticated intelligence-gathering equipment frequently finds it difficult or impossible to locate tunnel openings since they are frequently buried beneath terrain, flora, and other structures.
The tunnels have been dug by Gaza’s militias for close to 40 years, and over that time, they have improved in length, sturdiness, and intricacy. For instance, in 2022, Israeli special forces found a Hamas tunnel 230 feet (70 meters) below ground that could withstand even the most powerful Israeli bombings. In addition, the tunnels are quite inexpensive to construct; an after-action study on Operation Protective Edge from 2014 estimated an average cost of around $100,000 per tunnel (about the price of one Israeli Iron Dome Tamir interceptor) and a three-month building period.
Psychological Warfare
The IDF may find it difficult to recover from a morale crisis as a result of Hamas’ tunneling operations. Bradley Bowman, a security analyst based in Washington, told US media this week, “Imagine going into an environment and then you’re progressing across the field or into the outskirts of the city, and all of a sudden, some enemy forces pop up behind you where there were none there before.”
“That’s kind of a nightmare for an assaulting force,” he said. “Once you’re talking about block-to-block, building-to-building, room-to-room, in some cases, hand-to-hand fighting, it really gets pretty brutal pretty fast,” Bowman stressed.
IDF spokesman Jonathan Conricus acknowledged that eradicating Hamas would not be “an easy endeavor because Hamas has embedded itself inside and underneath the Gaza Strip,” and that it has previously utilized its maze of tunnels “to stop our weapons and hide countless rockets in all of these clashes that we’ve had.”
According to the Palestinian Health Ministry, at least 500 people died in the Gaza Hospital attack that occurred on Tuesday, which was claimed to be an IDF attack, but the Israeli military claims that the hospital was targeted when the Islamic Jihad organization Hamas accidentally fired a rocket.
Hamas’ tunnel systems have been referred to as a “nightmare” by West Point Modern War Institute expert John Spencer, who also cautioned that there is “no perfect solution” to the “problem” that will be “awaiting Israeli forces” if and when Tel Aviv decides to launch a land operation.
“Hamas will have already placed its leadership, fighters, headquarters, communication, weapons, and supplies like water, food, ammunition in its tunnel complexes to prepare for the ground assault by Israeli forces. The tunnels will allow fighters to move between a series of fighting positions safely and freely under massive buildings, even after the IDF drop thousand-pound bombs on them. Hamas tunnels often have generator power, air ventilation, water pipes, and stockpiles of food that will allow the group’s fighters to better withstand the most basic challenges, like normal exhaustion, that result from urban siege and isolation. Hamas leaders and fighters will use the tunnels to remain mobile to escape entire sections of the combat area when they feel they are about to be decisively attacked or surrounded,” the observer explained.
Tunnels, on the other hand, will enable Hamas to carry out surprise attacks against advancing enemy forces, infiltrating behind enemy lines and possibly wrecking havoc on rearward facing units with snipers, anti-tank gun and RPG-armed troops, and possibly even special “small hunter-killer teams” to pop up, strike, and slip back down into hidden tunnels, when facing off against Israeli troops forced on the offensive.
Israeli soldiers pursuing Hamas into the tunnels would encounter a number of time-consuming and hazardous challenges since navigation and communications equipment, as well as night vision goggles that depend on ambient light, would not function. “A single defender can hold a narrow tunnel against a much superior force,” Spencer observed.
Of course, IDF troops won’t be going underground defenseless; the Israeli army maintains whole specialized units whose sole responsibility is to locate and destroy tunnels, as well as units that work with specially trained dogs and deploy robots that can scout out and eliminate enemy forces without putting soldiers’ lives in danger.
“But the hard truth,” says Spencer, “is that the depth and scale of Hamas tunnels in Gaza will surpass Israel’s specialized capabilities.” Accordingly, “it may come down to IDF infantry and engineers dealing with tunnels as they discover them” the old fashioned way.
Lessons From Hezbollah
Hezbollah, a Lebanese militant organization, used tunnel warfare extensively against the Israeli troops in the 2006 Lebanon War. The 34-day, high-intensity conflict cost the IDF dearly, with just 1,000 well-trained Hezbollah fighters tying down ten to thirty times as many Israeli grunts while the IDF lost 121 soldiers, over 1,200 others, nearly two dozen tanks, and was forced to withdraw from southern Lebanon as a UN-brokered ceasefire came into effect.
Hezbollah reportedly “surprised” the IDF throughout the fight by the caliber of its preparation, strategies, and arsenal, particularly the skillful use of tunnels to emerge from cover, fire at the opposing forces, and then reappear underground before the IDF could react.
Hezbollah’s covert actions during the 2006 conflict were so successful that the US Army’s Complex Operational Environment and Threat Integration Directorate described it in a 2014 assessment as a “tactical, operational, and even strategic victory” for the militant group won through the successful “use of the subterranean environment.” It was determined that the “complex integrated network of underground tunnels and bunkers throughout southern Lebanon” had functioned “as a key component of its planned defense.”
The experience Hezbollah had against Israeli forces should give commanders and political decision-makers in Tel Aviv pause in the days, weeks, and months ahead, even though Hezbollah and Hamas are two very different militant organizations, with the Lebanese militia perceived to be at least a level above its Palestinian cousins in terms of training, capabilities, available weapons, and outside assistance.