Israel Begins Pumping Seawater Into Hamas’s Gaza Tunnels
Early effort to flood tunnels is one of several techniques aimed at destroying network that underpins Hamas’s operations
Israel’s military has begun to pump seawater into Hamas’s vast complex of tunnels in Gaza, according to U.S. 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 just one of several techniques Israel is using to try to clear the tunnels and destroy them.
A spokesperson for the Israeli defense minister declined to comment, saying the tunnel operations are classified.
Israeli officials say that Hamas’s vast underground system has been key to its operations on the battlefield. The tunnel system, they say, is used by Hamas to maneuver 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 300 miles and includes thick blast doors is still being evaluated by the Israelis, according to U.S. officials.
Flooding the tunnels, which would likely be a weekslong process, began around the time Israel added two more pumps to the five pumps installed last month and conducted some initial tests, U.S. 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 U.S. 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 face subterranean warfare in tunnels that could be booby-trapped.
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% 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 [theater] 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 neighborhood of Gaza City, where it says Hamas keeps some of its fiercest fighters. Israeli Defense Minister Yoav Gallant said Monday evening 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, Eisin said, including dismantling the militant group’s battalions and reducing its members to operating as individuals at a very local level.
The spokesman for Hamas’s armed wing, Abu Ubaida, said Sunday that the group’s fighters had been able to repel Israeli forces in the strip.
Israel has used robots, dogs and drones to explore the tunnels under Gaza and has used liquid explosives and airstrikes to destroy them, among other methods. It has also considered flooding them with seawater.
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 cease-fire, either by international pressure or in negotiations to release the hostages still held by Hamas.
As Israel consolidates its territorial control, its military and defense officials have increasingly called upon militants in Gaza to surrender. Israeli military spokesman Daniel Hagari said Monday evening 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.
Jacob Nagel, a former Israeli national security adviser, said that if Israel can take control of Khan Younis above ground, then Hamas would be left without any of its important command-and-control centers, which could accelerate the pace of surrenders by low-level fighters.
More than two months into the fighting, Israel’s tactical achievements have yet to convert into strategic progress, said Eisin. “If we have until the end of January, we will most likely achieve the strategic aim of dismantling the bulk of Hamas’s military capabilities,” she said.
Israel though is unlikely to achieve its war goal of returning the almost 140 hostages still held by Hamas directly through force, Eisin added.
Israeli officials estimate the country’s military has killed at least 7,000 Hamas militants since the start of the war on Oct. 7, when militants from Gaza killed 1,200 people in southern Israel, according to Israeli authorities.
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 U.S. 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 Oct. 7 attacks on Israel, according to Israeli officials, who say the crossing’s use will double the aid that can enter the enclave.
The U.N. 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.
As Israel continued to bombard the strip, some 200 Palestinians were killed on Sunday, the Palestinian Health Ministry in Gaza said.
On Monday, two mothers were killed and several people were injured at northern Gaza’s Kamal Adwan Hospital, which the U.N. said Israeli forces had surrounded. About 3,000 people and dozens of patients have sheltered at the facility, unable to leave amid fighting in the vicinity between Israel and armed groups, the organization added.
Israel’s military said that it “continues to act against Hamas strongholds in the north of Gaza, among them the area of Beit Lahia,” and “takes all feasible precautions to mitigate harm to noncombatants, and is fighting against the Hamas terrorist organization, and not the civilians in Gaza or the medical teams operating there.”
The Israeli military said Tuesday that it recovered the bodies of two hostages held in Gaza since Oct. 7.
Eden Zakaria, 27, was kidnapped from an outdoor music festival, while Israeli soldier Ziv Dado, 36, was killed during Hamas’s initial attacks and his body was taken to the Strip.
Israel didn’t say how Zakaria died but said two additional soldiers were killed during an operation to recover Zakaria’s and Dado’s bodies, among them the son of a former Israeli military chief of staff and current war cabinet observer.
Gaza’s Health Ministry said Tuesday that Israeli forces gathered men including medical staff in Kamal Adwan’s courtyard, and it called for the International Committee of the Red Cross and other international groups to protect them.
Separately, medical charity Doctors Without Borders said one of its surgeons working at Al-Awda Hospital also in northern Gaza was injured by a shot fired from outside the facility. Israeli forces have surrounded the hospital in recent days.
The World Health Organization has stepped up calls for the protection of healthcare workers in Gaza. It said Israel detained and harassed two Palestine Red Crescent Society staff members in a U.N. convoy over the weekend. The convoy was on its way to deliver medical supplies to Al-Ahli Hospital in Gaza City when it was stopped at a checkpoint, the WHO said.
Israel’s military didn’t respond to requests for comment about the injured doctor and Red Crescent staff.