Rapidly expanding Israeli airstrikes across the Gaza Strip killed more than 700 people in the past day as medical facilities across the territory were forced to close because of bombing damage and a lack of power, health officials said on Tuesday.

The soaring death toll from Israel's escalating bombardment was unprecedented in the decades-long Israeli-Palestinian conflict.

It could signal an even greater loss of life in Gaza once Israeli ground forces backed by tanks and artillery launch an expected offensive into the territory aimed at crushing Hamas.

Gaza's 2.3 million people have been under increasing bombardment and running out of food, water and medicine since Israel sealed off the territory following the devastating October 7 attack by Hamas militants on towns in southern Israel.

On Tuesday, Israel said it had launched 400 airstrikes over the past day, killing Hamas commanders, hitting militants as they were preparing to launch rockets into Israel and striking command centres and a Hamas tunnel shaft.

The previous day, Israel reported 320 strikes. Witnesses and health officials said many of the airstrikes hit residential buildings, some of them in southern Gaza where Israel had told civilians to take shelter.

An overnight strike hit a four-storey residential building in the southern city of Khan Younis, killing at least 32 people and wounding scores of others, according to survivors.

The fatalities included 13 from the Saqallah family, said Ammar al-Butta, a relative who survived the airstrike. He said there were about 100 people there, including many who had come from Gaza City, which Israel has ordered civilians to evacuate.

“They were sheltering at our home because we thought that our area would be safe. But apparently, there is no safe place in Gaza,” he said.

Another airstrike hit a bustling marketplace in the Nuseirat refugee camp in central Gaza, killing several shoppers and wounding dozens, witnesses said.

Men used sledgehammers to break up concrete and dug with their bare hands through the jagged wreckage to save anyone they could — or at least recover the dead who had been buying meat and vegetables when the explosion hit.

A man buried up to his chest in rubble looked up at his rescuers with wide eyes, his face coated in dust from the blast. An oxygen mask was placed on his face as they spent 15 minutes working to free him.

Gaza's Hamas-run health ministry said the attacks killed at least 704 people over the past day, including 305 children and 173 women. More than 5,700 Palestinians have been killed in the war, including some 2,300 minors, the ministry said, without giving a detailed breakdown. The figure includes the disputed toll from an explosion at a hospital last week.

Most of the Palestinians killed since October 7 were in the north and central areas of the enclave that Israel had told them to evacuate, the ministry said.

The fighting has killed more than 1,400 people in Israel.

As the death toll in Gaza spiralled, facilities to deal with the casualties were dwindling. A total of 46 out of 72 primary healthcare facilities, and 12 out of 35 hospitals, stopped functioning, the World Health Organization said.

Palestinian health officials said the lack of electricity and fuel to power generators from the Israeli blockade, as well as damage from airstrikes, has forced many of the facilities to close.

Gaza's five main hospitals were all filled beyond capacity, it said.