1 of 6 The Hamas leader in Gaza has said in the past that the region has 500 km of tunnels Photo: GETTY / BBC The Hamas leader in Gaza has said in the past that the region has 500 km of tunnels Photo: GETTY / BBC
Israel says it is attacking parts of a secret labyrinth of tunnels built by Hamas under the Gaza Strip, continuing its retaliation for the Palestinian Islamist militant group’s unprecedented attack last Saturday (September 10).
“Imagine Gaza as one layer for civilians and another layer for Hamas. “We are trying to get to that second level that Hamas has built,” an Israel Defense Forces (IDF) spokesman said in a video on Thursday.
“These are not bunkers for the civilian population in the Gaza Strip. They only serve Hamas and other terrorists so that they can continue to fire rockets at Israel and plan operations to fire terrorists at Israel,” he said.
It is very difficult to estimate the size of the network, which Israel calls the “Gaza Metro,” which is located in an area that is only 41 km long and 10 km wide.
After a conflict in 2021, the IDF said it destroyed more than 100 km of tunnels through airstrikes.
However, Hamas said its tunnels stretched over 500 km and that only 5% had been reached.
For reference, the London Underground, one of the largest in the world, is 400 km long and runs mostly above ground.
2 of 6 Hamas tunnel system Photo: Israel Defense Forces Hamas tunnel system Photo: Israel Defense Forces
Construction of the tunnels began in Gaza before Israel withdrew its troops and settlers in 2005.
But after Hamas took control of the Gaza Strip two years later, the situation worsened, leading Israel and Egypt to restrict the entry and exit of goods and people for security reasons.
At its peak, nearly 2,500 tunnels running under the Egyptian border were used by Hamas and other militant groups to smuggle commercial goods, fuel and weapons.
Smuggling became less important for Gaza after 2010, when Israel began allowing more goods to be imported.
Egypt later stopped the smuggling by flooding or destroying the tunnels.
3 out of 6 tunnels have been dug under the Egyptian border to bring in all kinds of goods and weapons Photo: Getty/BBC Tunnels have been dug under the Egyptian border to bring in all kinds of goods and weapons Photo: Getty/BBC
Hamas and other factions began digging tunnels to attack Israeli forces.
In 2006, militants used one below the border with Israel to kill two Israeli soldiers and capture a third, Gilad Shalit, whom they held captive for five years.
In 2013, the IDF discovered a 1.6 km long and 18 m deep concretelined tunnel after residents reported hearing “strange noises.”
It went from the Strip to near an Israeli kibbutz.
The following year, Israel cited the need to eliminate the threat of attacks by militants using “terrorist tunnels” under the border to justify a major air and ground offensive in Gaza.
The IDF said it destroyed more than 30 tunnels during the war. But a group of militants also managed to use one of them to organize an attack that left four Israeli soldiers dead.
4 of 6 Gaza tunnels identified by Israel in 2014 Photo: Israel Defense Forces, Google Gaza tunnels identified by Israel in 2014 Photo: Israel Defense Forces, Google
“The tunnels that cross the border are generally rudimentary, meaning they have almost no fortifications. They are dug with one purpose: to invade Israeli territory,” says Daphné RichemondBarak, an underground warfare expert who teaches at the University of Israel. Reichman, in Israel.
“The tunnels in Gaza are different because Hamas uses them regularly. They are likely to be more comfortable for staying for longer periods. They are definitely prepared for a longer presence,” he says
“That’s where the leaders hide, they have command and control centers, they use them as transport and communication lines. They are equipped with electricity, lighting and tracks. It is possible to move more and stay on your feet.”
She says Hamas appears to have “perfected the art” of tunneling and warfare in recent years, having learned much from the tactics of Syrian rebels in Aleppo and Islamic State (IS) militants in Mosul.
Tunnels in the Gaza Strip are believed to lie up to 30 meters below the surface and have entrances on the lower floors of homes, mosques, schools and other public buildings to prevent militants from getting caught.
The construction of the network also entailed costs for the local population. The IDF accused Hamas of embezzling millions of dollars donated to Gaza in aid to finance the tunnels, as well as tens of thousands of tons of cement intended to rebuild homes destroyed in previous wars.
It is possible that Hamas militants used a crossborder tunnel in last weekend’s attacks in Israel that killed at least 1,300 people, most of them civilians, and took more than 150 others hostage.
A tunnel exit was reportedly discovered near Kibbutz Kfar Aza, where dozens of civilians were massacred.
If confirmed, the tunnel would have been built under the underground concrete barrier equipped with sophisticated antitunnel detection sensors that Israel installed in late 2021.
Expert RichemondBarak says this would be a shock, but points out that no tunnel detection system is infallible. “That’s why tunnels have always been used in wars, because there’s no way to avoid them.”
5 of 6 Fence on Israel’s border with Gaza Photo: UN Fence on Israel’s border with Gaza Photo: UN
She warns that it is unrealistic to believe that it is possible to destroy the entire network of Hamas tunnels in Gaza while hundreds of thousands of troops are concentrated nearby for a possible ground operation.
“There will be parts of the network where, for whatever reason, civilians will not be evacuated… Some parts of the underground network are unknown. And for some of them the collateral damage will be too high.”
The destruction of the tunnels will also result in significant loss of life including Israeli forces on the ground, Palestinian civilians and hostages, she says.
More than 1,500 Palestinians in Gaza, many of them civilians, have been killed in Israeli retaliatory attacks since Saturday.
“Hamas is very good at using human shields. When an attack is imminent, they place innocent civilians on top of buildings. This has forced Israel to call off attacks many times,” says RichemondBarak.
“Hamas could easily use this technique in the context of tunnels and easily place Israeli, American and other hostages in them.”
During the conflict in 2021, a series of devastating airstrikes in Gaza City leveled three residential buildings and killed 42 people. The IDF said they were targeting underground tunnels, but when these collapsed, the building’s foundations also collapsed.
6 of 6 Three buildings collapsed in Gaza City in 2021 after nearby tunnels were hit by an Israeli airstrike Photo: AFP Three buildings collapsed in Gaza City in 2021 after nearby tunnels were hit by an Israeli airstrike Photo: AFP
The tunnel network, according to RichemondBarak, was also intended to nullify the IDF’s advantages in technology and intelligence, increase the difficulty of urban warfare and pose a deadly threat to Israeli troops.
“First, Hamas had a lot of time to set traps for the entire network,” she says. “They could just let the soldiers into the tunnel network and end up blowing everything up.”
“They could kidnap [os soldados em ataques surpresa]. And then there are all the other risks: the lack of oxygen, fighting the enemy in close combat and rescuing wounded soldiers become virtually impossible.”
She adds: “Even if you don’t go into the tunnel, protecting an area where you suspect tunnels is very different to protecting an area in general. Here you have to protect something that is invisible.”
However, the Israel Defense Forces will have some options to mitigate the risks.
According to Colin Clarke, head of research at security consultancy Soufan Group, this could include sending drones and unmanned vehicles into tunnels to map them and identify traps.
Warplanes can also drop “bunker buster” bombs that penetrate deep into the ground before being detonated.
However, due to the region’s dense urban terrain, there is a risk of collateral damage.
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