JERUSALEM (AP) — Palestinians lined up outside bakeries and grocery stores in Gaza on Thursday after spending the night surrounded by the ruins of pulverised neighbourhoods darkened by a near-total power outage. Israel launched new airstrikes and said it was preparing for a possible ground invasion.

International aid groups warned that the death toll in Gaza could mount after Israel stopped all deliveries of food, water, fuel and electricity to the tiny enclave while its crossing with Egypt is unusable. The war — which was ignited by a bloody and wide-ranging assault on Israel by Hamas militants — has already claimed at least 2,600 lives on both sides.

Lieutenant Colonel Richard Hecht, an Israeli military spokesman, told reporters Thursday that forces “are preparing for a ground maneuver” should political leaders order one. A ground offensive in Gaza, whose 2.3 million residents are densely packed into a sliver of land only 40 kilometres (25 miles) long, would likely bring even higher casualties on both sides in brutal house-to-house fighting.

As Israel pounds Gaza from the air, Hamas fighters have fired thousands of rockets into Israel since their weekend assault. Militants in the territory are also holding an estimated 150 people taken hostage from Israel.

Palestinians fleeing airstrikes could be seen running through the streets, carrying their belongings and looking for a safe place. Tens of thousands have crowded into United Nations-run schools while others are staying with relatives or even strangers who let them in.

Lines formed outside bakeries and grocery stores during the few hours they dared open, as people tried to stock on food before shelves are emptied. On Wednesday, Gaza’s only power station ran out of fuel and shut down, leaving only lights powered by scattered private generators.

A senior official with the the International Committee of the Red Cross warned that the lack of electricity could cripple hospitals.

“As Gaza loses power, hospitals lose power, putting newborns in incubators and elderly patients on oxygen at risk. Kidney dialysis stops, and X-rays can’t be taken,” said Fabrizio Carboni, ICRC’s regional director. “Without electricity, hospitals risk turning into morgues.”

Israeli Energy Minister Israel Katz said nothing would be allowed into Gaza until the captives were released. “Not a single electricity switch will be flipped on, not a single faucet will be turned on, and not a single fuel truck will enter until the Israeli hostages are returned home,” he tweeted.

After Hamas militants stormed into Israel on Saturday and massacred hundreds of people in their homes, on the streets and at an outdoor music festival, Israeli Prime Minister Benjamin Netanyahu vowed to “crush” the group, which has governed Gaza since 2007. A new war Cabinet, which includes a longtime opposition politician, is now overseeing the fight.

The Israeli government is under intense public pressure to topple Hamas rather than continuing to try to bottle it up in Gaza after four previous conflicts ended with the group still firmly in charge of the territory. Israel has mobilized 360,000 reservists, massed additional forces near Gaza and evacuated tens of thousands of residents from nearby communities.

The US has pledged unwavering support, and Secretary of State Antony Blinken arrived in Tel Aviv on Thursday to meet with Israeli leaders. He plans to meet Friday with Palestinian President Mahmoud Abbas, whose authority is confined to the occupied West Bank, and Jordan’s King Abdullah II.

“You may be strong enough on your own to defend yourselves, but as long as America exists you will never have to,” Blinken said after meeting with Netanyahu. “We will always be there by your side.”

Israel captured the West Bank, along with Gaza and east Jerusalem, in a 1967 war. The Palestinians want all three territories for their future state, but there have been no peace talks in over a decade.