KHAN YOUNIS, Gaza Strip — Internet and telephone services collapsed across the Gaza Strip on Thursday for lack of fuel, the main Palestinian provider said, bringing a potentially long-term blackout of communications as Israel signaled its offensive against Hamas could next target the south, where most of the population has taken refuge.

Israeli troops for a second day searched Shifa Hospital in the north for traces of Hamas. They displayed what they said were a tunnel entrance and weapons found in a truck inside the compound. But the military has yet to release evidence of a central Hamas command center that Israel has said is concealed beneath the complex.

Hamas and staffers at the hospital, Gaza’s largest, deny the allegations.

The military said it found the body of one of the hostages abducted by Hamas — Yehudit Weiss, 65 — in a building adjacent to Shifa, where it said it also found assault rifles and rocket-propelled grenades.

Weiss is the third hostage confirmed dead, while four others have been freed and one rescued. The military did not give the cause of death.

The communications breakdown largely cuts off Gaza’s 2.3 million people from each other and the outside world, worsening the severe humanitarian crisis in southern Gaza, even as Israeli airstrikes continue there. The U.N.’s World Food Program warned of “the immediate possibility of starvation” in Gaza as the food supply has broken down under Israel’s seal and too little is coming from Egypt.

The war, now in its sixth week, was triggered by Hamas’ Oct. 7 attack into southern Israel in which the militants killed over 1,200 people, mostly civilians, and captured some 240 men, women and children.

Israel responded to the attack with a weekslong air campaign and a ground invasion of northern Gaza, vowing to remove Hamas from power and crush its military capabilities.

More than 11,470 Palestinians have been killed, two-thirds of them women and minors, according to Palestinian health authorities. Another 2,700 have been reported missing, believed buried under rubble. The official count does not differentiate between civilian and militant deaths, and Israel says it has killed thousands of fighters.

The war has inflamed tensions elsewhere.

In the occupied West Bank, Palestinian gunmen opened fire at a checkpoint on the main road linking Jerusalem to Israeli settlements, killing a soldier and wounding three people.

The three attackers were killed, according to police, who said the assailants had assault rifles, handguns and hatchets, and were preparing an attack in Jerusalem. Hamas claimed responsibility for the attack.

A day after storming into Shifa, Israeli troops continued searching the hospital complex. Gaza’s Health Ministry said the troops searched underground levels of the hospital Thursday and detained technicians who run its equipment.

The hospital has not had electricity for nearly a week, and staffers say they have been struggling to keep alive 36 premature babies and 45 dialysis patients without functional equipment.

One dialysis patient died Thursday, Shifa’s director, Mohamed Abu Selmia, told Al Jazeera, adding that 650 wounded patients and 5,000 displaced people are in the hospital.

Israel said its soldiers brought medical teams with incubators and other supplies, though Shifa staffers said incubators were useless without fuel. Gaza’s Health Ministry said 40 patients, including three babies, died before the raid after the emergency generator ran out of fuel Saturday.

During previous days of fighting in the nearby streets, there was no report of Hamas fighters firing from inside Shifa, and no fighting when Israeli troops entered Wednesday.

Israel faces pressure to prove its claim that Hamas set up its main command center in and under the hospital, which has multiple buildings over an area of several city blocks.

On Thursday, the military released video of a hole in the hospital courtyard it said was a tunnel entrance. It also showed several assault rifles and RPGs, grenades, ammunition clips and utility vests laid out on a blanket that it said were found in a pickup truck in the courtyard.

The Associated Press could not independently verify the Israeli claims.

In recent weeks, Israel depicted the hospital as the site of a major Hamas headquarters. The U.S. said it has intelligence to support Israeli claims.

The allegations are part of Israel’s broader accusation that Hamas uses Palestinians as human shields across the Gaza Strip — which Israeli officials say is the reason for the large numbers of civilian casualties during weeks of bombardment.

Israeli forces dropped leaflets Thursday telling Palestinians in areas east of the southern town of Khan Younis to evacuate. Similar leaflets were dropped over northern Gaza for weeks ahead of the ground invasion.

Strikes continued in the south Thursday.

In the city of Deir al-Balah, a funeral was held for 28 people killed overnight by a bomb that leveled several buildings.

Most of Gaza’s population is crowded into southern Gaza. Some 1.5 million people driven from their homes have packed into U.N. shelters or houses with other families.

If the assault moves deeper south, it is not clear where the Palestinians would go, as Egypt refuses to allow a mass transfer onto its soil.