An Israeli airstrike hit a school-turned-shelter in Gaza City early Saturday, killing more than 60 people, Palestinian health authorities said, in one of the deadliest strikes in the 10-month-old war between Israel and Hamas.

The Israeli military acknowledged the strike, claiming it hit a Hamas command centre within the school. Hamas denied using the school as a command centre.

The strike on the Tabeen school in central Gaza City also wounded 47 people, the Health Ministry's Ambulance and Emergency service said. The facility, like almost all of Gaza's schools, has been used as a shelter for people who have been forced to flee their homes by the war.

The strike hit without warning in the early morning before sunrise as people were praying at a mosque inside the school, according to Abu Anas, a witness who worked to rescue people.

“There were people praying, there were people washing and there were people upstairs sleeping, including children, women and old people," he said. “The missile fell on them without warning. The first missile, and the second. We recovered them as body parts.”

Three missiles ripped through the school and the mosque inside, where about 6,000 displaced people were taking shelter from the war, said Mahmoud Bassal, a spokesperson for the Civil Defence first responders who operate under the Hamas-run government.

Many of the dead were unrecognisable, he said, adding that he expected the death toll to rise. Many of the casualties were women and children, he said.

According to the United Nations, 477 out of 564 schools in Gaza have been directly hit or damaged in the war as of July 6. In June, an Israeli strike on a school sheltering displaced Palestinians in central Gaza killed at least 33 people, including 12 women and children, according to local health officials.

Israel has blamed civilian deaths in Gaza on Hamas, saying the group endangers noncombatants by using schools and residential neighbourhoods as bases for operations and attacks.

In its statement Saturday, the Israeli military claimed Hamas militants used the school as a base to plan attacks on Israeli forces, without providing evidence. It said the school was located next to a mosque serving as a shelter for Gaza City residents.

The strike came as American, Qatari and Egyptian mediators renewed their push for the two parties to achieve a cease-fire agreement that could help calm soaring tensions in the region following the assassination of top Hamas political leader Ismail Haniyeh in Tehran and a senior Hezbollah commander in Beirut.

Egypt, which borders Gaza and serves as a key mediator, said the strike on the school showed Israel had no intention of reaching a cease-fire deal and ending the war.

Israel's campaign in Gaza has killed more than 39,600 Palestinians and wounded more than 91,700 others, according to the enclave's Health Ministry. The war was triggered by Hamas' Oct 7 attack, in which militants from Gaza stormed into southern Israel, killing around 1,200 people and abducting 250 others.

More than 1.9 million of Gaza's pre-war population of 2.3 million have been driven from their homes, fleeing repeatedly across the territory to escape offensives. Most are now crowded into ramshackle tent camps in an area of about 50 square kilometres (19 square miles) on the Gaza coast.