How is Israel preparing to destroy the tunnels An almost impossible mission that resembles science fiction movies
Financial Times
The small IDF drone inside an arched concrete corridor continued to fly for several minutes, along a 300-meter tunnel large enough for a tall man to walk without bending over.
To the left and right there were rooms with air conditioning units, toilets, kitchens with running water, as well as electrical and communication cables, and a now demolished explosion-proof door through which Hamas fighters could fire.
The tunnel, which the IDF said they filmed last month under Gaza's Shifa Hospital, was only a small part of Hamas ' vast underground domain that officials and analysts said would determine the strategic outcome of Israel's campaign against the militant group.
The motivation to find fighters and weapons in Hamas tunnels and demolish the network itself is one of the reasons why the IDF is pressing ahead with its punitive offensive after a week-long truce, despite the growing international pressure on the bloodiest Israeli-Palestinian conflict in decades.
Daphne Richmond Barak, a professor at Israel's Reichman University and author of a book on underground fighting, said: "destroying Hamas tunnels is the most difficult aspect of the IDF's mission. . . Among the most important are". "We must be patient."It will take some time."
The tunnel network, estimated to be larger than the London Underground train network, enables senior Hamas leaders and fighters to take cover. Most of them are believed to have survived nearly eight weeks of relentless Israeli underground assault.
The tunnels-immune from drone surveillance and many of Israel's other capabilities including airstrikes - are believed to be where Hamas keeps its arsenal of rockets, as well as the more than 130 hostages it still holds after capturing them from Israel in its devastating offensive on October 7.
A former senior Israeli security official said that the word "tunnels "did not do justice to what Hamas had created in Gaza, describing them as"underground cities".
Yochefed Lifshitz, an 85-year-old hostage released by Hamas in October, described the tunnel network as an elaborate "spider web" "kilometers long" with a "large hall" large enough to hold 25 people.
Tunnels are an ancient technique for fighting a war. Jewish rebels used it in a famous revolt against Roman rule 2,000 years ago, as did the Viet Cong fighters who eventually defeated American troops in the Vietnam War.
But after drilling the geology of the soft sandstone in Gaza since taking control of the Strip 16 years ago, Hamas has taken the concept to a new level.
"The modern battlefield is experiencing a combination of outdated and digital capabilities,"said Anthony King, an urban warfare expert at the University of Exeter. "And sometimes it's the old technologies [such as tunnels] that can win and beat the rest."
The IDF has made the destruction of the tunnels a priority, but has not fully detailed how it plans to achieve this. So far, it has located more than 800 columns, destroyed 500 of them and collapsed what the IDF described as "miles" of tunnels.
"At the tactical level, at the maneuver sites of our soldiers [on the ground] we have a high success rate in destroying tunnels,"said a person familiar with Israeli military planning.
But the length of the network is estimated to be more than 500 km, and many columns appear in civilian buildings such as hospitals, mosques and schools, according to the IDF.
The IDF said on Sunday that its fighter jets and helicopters "hit terrorist targets in the Gaza Strip, including terrorist tunnel columns," after the collapse of a truce that enabled the exchange of dozens of Israeli hostages for more than 200 Palestinian prisoners.
Israeli forces now control much of northern Gaza, at least above ground. However, even after the takeover, IDF soldiers still face attacks from Hamas militants who emerge from the tunnels behind them and then retreat "like rats," as one officer told local media.
This resistance helped prolong the fighting, increase the death toll of Israeli fighters, and erode international support for the Jewish state as Palestinian civilian casualties mounted.
Tunnels also pose a threat in themselves. The IDF said that four soldiers were killed on November 10 at the entrance to one tunnel in the northeastern corner of Gaza. More than 70 Israeli soldiers have been killed since the IDF launched its ground offensive on October 27.
"The tunnels are a huge challenge,"said one Israeli official. "They [Hamas] have also placed things inside - booby traps, obstacles to our movement inside the tunnels - that increase the risks [to our troops]."
The IDF last week blew up the tunnel it found under the Shifa hospital, amid fears that the rest of the network was mined with explosives.
Israeli officials said Hamas had learned from previous attacks. This includes the 5,000-pound GBU-28 laser-guided "bunker buster" bombs that Israel is said to have used during the 2021 offensive against the militant group aimed at destroying the "Gaza Metro", as it is known. That operation had only limited success.
Yehuda Kfir, an Israeli civil engineer and a commander in the IDF reserves who is also an expert on underground warfare, said: "the lesson Hamas probably learned from the 2021 air strikes. . . It is digging deeper and encasing the tunnel system with reinforced concrete,"he said.
"It is likely that Hamas has built different layers of tunnels,"kafir added. An upper "defensive" level with booby traps, very narrow [tunnels] and explosion-proof doors that we have already seen, and an "offensive" level that is deeper, wider and holds such things as logistics centers, living quarters and weapons stores."
The armed group also built smuggling tunnels to Egypt, which Cairo sought to demolish.
Israel has received 320 million dollars of US military assistance since 2016 for the development of anti-tunnel technologies.
The country also has a dedicated corps of anti-tunnel engineers and underground commandos equipped to investigate tunnels and attempt their collapse. But to keep the soldiers alive, the IDF relied more on tunnel dogs, robots and drones.
"The [Israeli] government is facing bureaucratic bottlenecks and pouring more resources into finding a solution,"an Israeli official said.
The first step is to determine the location of the tunnels. Ground-penetrating radar and acoustic sensors can work, although the dense urban environment of Gaza and the rubble left by Israeli aerial bombardment limit their usefulness.
A simpler tactic, known as "purple hair", involves throwing a smoke bomb into the tunnel entrance, which is then sealed with expanded foam to see if smoke appears elsewhere.
The next step is to destroy the tunnels. Localized explosions cause only limited Falls, which can be removed or bypassed by the surviving fighters. Engineers and military experts said that to completely demolish a tunnel would require placing explosives along long sections of underground passages.
One of the ways is to use liquid explosives that fill the tunnel space and then explode, Kfir said. Another possibility, he said, is thermal weapons, which absorb oxygen to generate a high-temperature explosion that flows around obstacles. But these are controversial due to the wider impact of explosions, especially in populated areas.
Pumping into Mediterranean water at high pressure is a third option, and Israel has reportedly already started using it. Richmond Barak said that this technology has the advantage of already being used in the oil and gas industry. But she added that the problem with flooding is "you don't know how much you have achieved".
The amount of water required depends on the size of the tunnels and the absorption of the earth, she said: "in the past, the use of water has not yielded a decisive result.
Another possibility, which would pose less of a danger to hostages than floods or explosions, is for the IDF to dig tunnels that intercept the Hamas network and break into its control nodes.
Kfir said: "Israel must. . . Getting to the heart of the Hamas regime is not from above, but from below,"he said. "You will need something like automated drilling machines. . . That would dig towards the goal."
These science fiction-like methods highlight the difficulties and time required to destroy the Hamas underground world. They also explain why some officials regret that Israel did not complete the task years ago.
"We should have destroyed everything when [Hamas' tunnel network] was smaller."We had all the intelligence,"the former senior security official said.
