Israel begins pumping seawater into Hamas tunnels

Israel’s military has begun pumping seawater into Hamas’s vast complex of tunnels in Gaza, according to US officials.

Israeli soldiers in a tunnel dug by Hamas militants inside the Al-Shifa hospital complex in Gaza City. Picture: AFP

Israel’s military has begun pumping seawater into Hamas’s vast complex of tunnels in Gaza, according to US officials briefed on the Israeli military’s operations, part of an intensive effort to destroy the underground infrastructure that has underpinned the group’s operations.

The move to flood the tunnels with water from the Mediterranean, which is in an early stage, is one of several techniques Israel is using to try to clear and destroy the tunnels.

A spokesperson for the Israeli Defence Minister declined to comment, saying the tunnel operations are classified.

Israeli officials say that Hamas’s underground system has been key to its operations on the battlefield. The tunnel system, they say, is used by Hamas to manoeuvre fighters across the battlefield and store the group’s rockets and munitions, and enables the group’s leaders to command and control their forces. Israel also believes some hostages are being held inside tunnels.

The utility of using seawater in a vast underground labyrinth that extends for roughly 550km and includes thick blast doors is still being evaluated by the Israelis, according to US officials.

Flooding the tunnels, which would likely be a weeks-long process, began around the time Israel added two more pumps to the five pumps installed last month and conducted some initial tests, US officials said.

Some Biden administration officials have been concerned that using seawater might not be effective and could endanger Gaza’s freshwater supply. Egypt in 2015 used seawater to flood tunnels operated by smugglers under the Rafah border crossing with Gaza, prompting complaints from nearby farmers about damaged crops.

But other US officials say the technique might help destroy portions of the tunnel network. The Wall Street Journal has previously reported that flooding the tunnels with seawater was under consideration.

Military analysts have assessed that Israel hasn’t destroyed most of this tunnel network and that a variety of techniques will be needed to destroy or damage the underground system. In addition to the seawater, the Israeli military has sought to attack the network with airstrikes and liquid explosives, and by sending in robots, dogs and drones.

Israel’s military said it was intensifying operations underground in northern Gaza and beneath the southern city of Khan Younis, one of Hamas’s last strongholds. The underground labyrinth remains one of Israel’s main challenges to achieving its goal of destroying Hamas’s military capabilities both in areas it controls above ground and those where it so far hasn’t operated. The tunnels under the southern city of Rafah near the Egyptian border for example, analysts say, are used by Hamas to smuggle most of its weapons into Gaza.

Israel’s military has been reluctant to send soldiers underground, where they would lose their tactical firepower advantage and encounter booby-traps.

Speaking from Khan Younis on Monday, Israel’s top general, Herzi Halevi, said, “We are deepening our control over northern Gaza and our penetration into the southern strip, and also deepening activity underground.”

Israel has control of around 40 per cent of the coastal enclave above ground, according to military analysts, who say that Hamas’s tunnels pose the greater obstacle.

“The territorial issue is not the issue, the problem is Hamas is going underground,” said former Israeli military intelligence chief Amos Yadlin.

Even in the areas that Israel has taken, “the subterranean [theatre] continues to be the challenge”, said Miri Eisin, a retired colonel in Israel’s military intelligence.

Israel’s forces have encircled Jabalia in northern Gaza and the Shujaiya neighbourhood of Gaza City, where it says Hamas keeps some of its fiercest fighters. Israeli Defence Minister Yoav Gallant said that northern Gaza was at its “breaking point” and that Hamas was “on the verge of collapse” there.

Israel’s definition of control means having broken Hamas’s formal command structure, Mr Eisin said, including dismantling the militant group’s battalions and reducing its members to operating as individuals at a very local level.

Israeli military analysts say that taking control of Khan Younis would trap Hamas’s remaining aboveground fighters between Israeli positions in northern and southern Gaza as well as between the Khan Younis area and the Egyptian border area. Israel hopes that Hamas’s weak fighting position and the killing of around half of the group’s battalion commanders will spur lower-level fighters to surrender en masse.

Hamas can prevent that outcome, military analysts say, by holding out underneath Gaza until Israel is forced into a ceasefire, either by international pressure or in negotiations to release the hostages still held by Hamas or other groups.

Israeli military spokesman Daniel Hagari said that more than 500 militants had surrendered to Israeli forces in the past month and that half of them were taken for further questioning in Israel.

Hamas has denied that militants have surrendered and said Israeli forces have arrested civilians.

Israel, though, is unlikely to achieve its war goal of returning the almost 140 hostages still held by Hamas directly through force, Mr Eisin added.

Israeli officials estimate the country’s military has killed at least 7000 Hamas militants since the start of the war on October 7, when militants from Gaza killed 1200 people in southern Israel.

More than 18,400 Palestinians have died in Gaza, two-thirds of them women and children, according to Palestinian health authorities. The figures don’t distinguish between militants and civilians.

Following pressure from the US and the United Nations, Israel on Tuesday began facilitating the movement of trucks of aid into Gaza from the Kerem Shalom crossing between Israel and Gaza. This is the first time the crossing has been used since it was damaged by Hamas during its October 7 attacks on Israel, according to Israeli officials, who say the crossing’s use will double the aid that can enter the enclave.

The UN has warned that aid that has been moving through the Rafah border crossing between Egypt and Gaza falls far short of what is required to deal with the increasingly dire humanitarian situation inside the enclave, and has called for commercial convoys to be allowed in through Kerem Shalom as well as aid.

The Wall Street Journal