Israel, signaling a possible expansion of operations in Gaza's south, dropped leaflets warning Palestinians to flee, residents reported Thursday, pressuring hundreds of thousands of people crowded into U.N.-run shelters and family homes who had already heeded earlier evacuation orders issued in the north.

If Israeli troops move south, it is not clear where Gaza’s population can flee, as Egypt refuses to allow a mass transfer onto its soil.

Meanwhile, soldiers continued searching Al-Shifa Hospital in the north, in a raid that began early Wednesday that has yet to uncover evidence of the central Hamas command center that Israel has claimed is concealed beneath the complex. Hamas and staff at the hospital, Gaza's largest, deny the allegations.

Broadening the offensive to the south – where Israel already carries out daily air raids – threatens to worsen an already severe humanitarian crisis in the besieged territory. Over 1.5 million people have been internally displaced in Gaza, with most having fled to the south, where food, water and electricity are increasingly scarce.

The war, now in its sixth week, was triggered by a wide-ranging Hamas attack into southern Israel on Oct. 7 that killed 1,200 people, mostly civilians, and captured some 240 men, women and children. Israel responded 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 11,200 Palestinians have been killed, two-thirds of them women and minors, according to Palestinian health authorities. Another 2,700 have been reported missing, with most believed to be buried under the rubble. The official count does not differentiate between civilian and militant deaths.

Israeli troops on Wednesday stormed into Gaza’s largest hospital, searching for traces of Hamas inside and beneath the facility, where newborns and hundreds of other patients have suffered for days without electricity and other basic necessities.

Troops were searching the underground levels of the hospital on Thursday and detained technicians responsible for running its equipment, the Health Ministry in Hamas-run Gaza said in a statement.

After encircling Shifa for days, Israel faced pressure to prove its claim that Hamas was using the patients, staff and civilians sheltering there to provide cover for its fighters. The allegation is part of Israel's broader accusation that Hamas uses Palestinians as human shields.

The military released video from inside Al-Shifa that showed three duffel bags it said it found hidden around an MRI lab, each containing an assault rifle, grenades and Hamas uniforms, as well as a closet that contained a number of assault rifles without ammunition clips. The Associated Press (AP) could not independently verify the Israeli claims that the weapons were found inside the hospital.

Patients' lives at stake

Hamas and Gaza health officials deny militants operate in Al-Shifa – a hospital that employs some 1,500 people and has more than 500 beds. The Palestinians and rights groups accuse Israel of recklessly endangering civilians.

Munir al-Boursh, a senior official with Gaza’s Health Ministry inside the hospital, said that for hours, the troops ransacked the basement and other buildings, including those housing the emergency and surgery departments, and searched the grounds for tunnels. Troops questioned and face-screened patients, staff and people sheltering in the facility, he said, adding that he did not know if any were detained.

"Patients, women and children are terrified," he told the AP by phone Wednesday.

The military said its troops killed four Hamas members outside the hospital at the start of the operation, but through days of fighting, there were no reports of members of Hamas firing from inside Al-Shifa. There were also no reports of any fighting within the hospital after Israeli troops entered.

The military said it was carrying out a "precise and targeted operation" in a specific area of the hospital, and that its soldiers were accompanied by medical teams bringing in incubators and other supplies.

At one point, tens of thousands of Palestinians fleeing Israeli bombardment were sheltering at Al-Shifa, but most left in recent days as the fighting drew closer. The fate of premature babies at the hospital has drawn particular concern.

The Health Ministry said 40 patients, including three babies, have died since the hospital's emergency generator ran out of fuel Saturday. There was no immediate word on the condition of another 36 babies, who the ministry said earlier were at risk of dying because there is no power for incubators.

The leaflets, dropped in areas east of the southern town of Khan Younis, warned civilians to evacuate the area and said anyone in the vicinity of Hamas fighters or their positions "is putting his life in danger." Similar leaflets were dropped over northern Gaza for weeks ahead of the ground invasion.

Two local reporters who live east of Khan Younis confirmed seeing the leaflets. Others shared images of the leaflets on social media.

Defense Minister Yoav Gallant said Wednesday the ground operation will eventually "include both the north and south. We will strike Hamas wherever it is."

The military says it has largely consolidated its control of the north, including seizing and demolishing government buildings. Video released by the army Thursday showed soldiers moving between heavily damaged buildings through holes blown in their walls.

On Thursday, the military said it had blown up a residence belonging to Ismail Haniyeh, a senior Hamas leader based abroad. It was unclear if anyone was inside the building.

Most of Gaza’s 2.3 million people have already crowded into the territory’s south, where a worsening fuel shortage threatens to paralyze the delivery of humanitarian services and shut down mobile phone and internet service.

Conditions in southern Gaza have been deteriorating as bombardment continues to level buildings. Residents say bread is scarce and supermarket shelves are bare. Families cook on wood fires for lack of fuel. Central electricity and running water have been out for weeks across Gaza.

Israel allowed a small amount of fuel to enter Gaza on Wednesday, for the first time since the war began, so that the U.N. agency for Palestinian refugees, which is providing basic services to hundreds of thousands of people, could continue bringing limited supplies of aid through the Rafah crossing with Egypt.

The fuel cannot be used for hospitals or to desalinate water, and covers less than 10% of what the agency needs to sustain "lifesaving activities," said Thomas White, the agency’s Gaza director.

The Palestinian telecom company Paltel, meanwhile, said it expected services to halt later Wednesday because of the lack of fuel or electricity. Gaza has experienced three previous mass communication outages since the ground invasion.