The Israeli army said Tuesday it is channelling water into Gaza's tunnels in a bid to destroy the sprawling underground network used by Hamas militants to launch attacks on Israel.

This picture taken during a media tour organized by the Israeli military on December 15, 2023, shows a tunnel that Hamas reportedly used to attack Israel through the Erez border crossing on October 7.

"It is part of a range of tools deployed by the IDF (Israeli army) to neutralise the threat of Hamas's subterranean network of tunnels," the military said in a statement, confirming media reports.

Dubbed "the Gaza metro" by the Israeli army, there were 1,300 tunnels over 500 kilometres (310 miles) in Gaza at the start of the war in October, according to a study from US military academy West Point.

The military vowed to destroy them in the wake of Hamas's October 7 attack in southern Israel that resulted in the deaths of around 1,140 people, mostly civilians, according to an AFP tally based on official Israeli figures.

Some 250 hostages were also dragged to Gaza during the October 7 attack, of which around 132 are still held captive, including bodies of at least 28 people believed to have been killed.

Since the Hamas attack, Israel has launched a withering air, land and sea offensive in Gaza that has killed at least 26,751 people, mostly women and children, according to the health ministry in the territory.

The Israeli army says that many hostages taken by Hamas have been or continue to be held in the vast network of tunnels.

In December some Israeli media reported the military was leaning towards flooding the tunnels with seawater pumped from the Mediterranean.

But experts had warned the option was dangerous and poses huge risks to Gaza's besieged civilians.

"It will cause severe damage to the already fragile water and sewage infrastructure that's in Gaza," the then UN humanitarian coordinator for Palestinian territories, Lynn Hastings, had warned in December.

"There's even a risk to buildings and roads collapsing because of the increased pressure and infiltration of sea water into Gaza."

On Tuesday the army said it had taken care in a way as to not "damage the area's groundwater".

"The pumping of water was only carried out in tunnel routes and locations that were suitable, matching the method of operation to each case," it said.

"This tool is one of a range of capabilities developed by the IDF and Israel's security establishment in recent years in order to operate against Hamas' underground infrastructure in the Gaza Strip."

The maze of tunnels was initially used to bypass Israel's devastating blockade on the Gaza Strip after Hamas came to power in 2007, allowing the smuggling of people, goods and weaponry in and out of Egypt.

It extended the network after the 2014 Israel-Hamas war and uses them to emerge across Gaza to launch rocket attacks on Israel.

Israel floods Hamas attack tunnels, as mediators press for truce

Families of Israeli hostages held in the Gaza Strip gather with supporters for a demonstration demanding an immediate deal, in Tel Aviv on January 29, 2024.

Israel's army said Tuesday it was flooding Hamas's attack tunnels amid intense fighting in Gaza, even as international mediators pushed for a new halt in the nearly four-month war.

The epicentre of the fighting has been Khan Yunis, southern Gaza's main city where vast areas have been reduced to a muddy wasteland of bombed-out buildings.

The Israeli military said it had adopted the tactic of channelling water into Hamas's vast underground network of tunnels that it has dubbed "the Gaza metro".

"It is part of a range of tools deployed by the IDF (Israeli army) to neutralise the threat of Hamas's subterranean network of tunnels," it said, confirming media reports.

At the start of the Israel-Hamas war in October, there were 1,300 tunnels over 500 kilometres (310 miles) in Gaza, according to a study from US military academy West Point.

The army vowed to destroy them in the wake of Hamas's October 7 attacks on Israel that resulted in the deaths of around 1,140 people, mostly civilians, according to an AFP tally based on official Israeli figures.

Some 250 hostages were also dragged to Gaza during the October 7 attack, of which around 132 are still held captive, including bodies of at least 28 people believed to have been killed.

Since the Hamas attack, Israel has launched a withering air, land and sea offensive in Gaza that has killed at least 26,751 people, mostly women and children, according to the health ministry in the territory.

The military says many of the hostages taken by Hamas have been or continue to be held in the vast network of tunnels.

In December, some Israeli media said the army was leaning towards flooding the tunnels with seawater pumped from the Mediterranean, but experts warned it was dangerous and poses huge risks to civilians.

On Tuesday, the military said it had taken care not to "damage the area's groundwater".

- Truce talks -

In Khan Yunis, the Israeli army said its troops fighting in city blocks and tunnels had "eliminated terrorists during combat and located large quantities of weapons".

Islamic Jihad, a Palestinian militant group fighting alongside Hamas, said it was battling Israeli forces near Khan Yunis and in other areas including Gaza City.

In the latest efforts to broker a new truce, a meeting in Paris on Sunday between top US, Israeli, Egyptian and Qatari officials resulted in a proposed framework.

Hamas said on Tuesday it had received the proposal, saying on its Telegram account that it was "in the process of examining it and delivering its response".

Qatari Prime Minister Sheikh Mohammed bin Abdulrahman Al Thani, whose government helped broker a previous truce in November, voiced hope an initial deal might lead to a permanent ceasefire.

Sheikh Mohammed said the current plan included a phased truce that would see women and children hostages released first, with more aid also entering Gaza.

The United States expressed hope for a deal, with Secretary of State Antony Blinken saying "very important, productive work has been done".

Israeli Prime Minister Benjamin Netanyahu, whose office earlier also called the talks "constructive", ruled out releasing "thousands" of Palestinian prisoners as part of any deal to halt fighting in Gaza.

"I would like to make it clear... We will not withdraw the IDF from the Gaza Strip and we will not release thousands of terrorists. None of this will happen," he said Tuesday.

- Undercover hospital raid -

Violence has surged in the West Bank since the start of the war.

On Wednesday, Israeli undercover troops raided a hospital in Jenin, in the north of the Israeli-occupied Palestinian territory, killing three men the army said were members of a "terrorist cell".

Some of the Israeli agents were dressed as medical staff and carried a wheelchair and baby carrier as props, according to officials and hospital CCTV footage released by the Ramallah-based Palestinian health ministry.

Hamas said one of the three killed, Muhammad Jalamnah, was a commander in its armed wing.

The Israeli army charged that Jalamnah, allegedly "inspired" by the October 7 attack, had "planned to carry out a terror attack in the immediate future and used the hospital as a hiding place".

The Palestinian health ministry said hospitals enjoy special protection under international law and urged the United Nations to help end Israel's "daily string of crimes... against our people and health centres".

In southern Gaza, Palestinians buried dozens of bodies in a mass grave after officials said Israel returned remains it had exhumed from the territory.

The Israeli military did not respond to a request to comment, although it has previously made remarks about exhuming bodies from Gaza graves in search of Israeli hostages.

- UNRWA 'distraction' -

Fears have grown that the Middle East could face a wider conflict, after months of violence involving Iran-backed allies of Hamas in Lebanon, Iraq, Syria and Yemen, who have also targeted US forces.

The war has left much of Gaza in ruins and sparked a spiralling humanitarian crisis for its 2.4 million people, many of whom face the threats of hunger and disease.

Israel has alleged that about a dozen staff of the main UN aid agency for Palestinians took part in the October 7 attack, leading key donor countries including the United States and Germany to suspend funding.

UN Secretary-General Antonio Guterres, who has pleaded for continued support to meet the "dire needs", will have talks with donors in New York on Tuesday, his office said, as investigations into Israel's claims continue.

The World Health Organization called the row over UNRWA "a distraction from what's really going on every day, every hour, every minute in Gaza".

Into the heart of the Gaza war with the IDF.

As part of a small group of journalists, Fox News embedded with the Israeli military in Gaza. I joined the IDF in Khan Younis, a current focal point of the Israeli operation.

Loading into vehicles, soldiers pull on gaiters and goggles to protect themselves on the dusty drive ahead.

Within a quarter of a mile into Gaza, troops stop to show the press the latest tunnel destroyed the night before. The ground’s been excavated. Wires are exposed. The IDF doesn’t elaborate on how it blew up this specific tunnel.

Climbing down into the crater, soldiers show the soft texture of the soil. This tunnel was only narrow enough to fit one or two people.

It’s fortified with cement. The IDF says the narrow entrance without a lid, meant it would’ve been easy to climb in or out quickly.

Driving deeper into Gaza, rubble lines the road. The war has flattened the suburbs of Khan Younis.

The piercing sound of artillery is constant.

The few buildings still standing are riddled with bullet holes. Troops stop at one such building. It’s a primary school.

The IDF says a gun battle played out here. Israeli soldiers claim Hamas stashed weapons here and dug a tunnel under the playground.

"We had a Hamas squad hiding in the basement of the school. They popped up and started shooting at us. And this is literally the story of this war," says Lt. Col. Anchy with the 55th Brigade.

There’s no front line in this war.

New plumes of smoke reveal the ground battles in every direction.

"We're just working very systematically, one zone after the other, dismantling their infrastructure," Anchy says.

The IDF recently announced it had encircled the city of Khan Younis, as it urges civilians to flee south.

The war has displaced nearly 2 million people. According to the United Nations, half of the strip’s population is now sheltering in the southern city of Rafah.