The Israeli military said on Saturday the air strike had targeted a Hamas command centre.
The strikes hit when people sheltering at the school were performing dawn prayers, leading to many casualties, the Hamas media office said in a statement.
Displacement continues for thousands of families across — UNRWA (@UNRWA) #Gaza. Yesterday, following evacuation orders in the Khan Younis area, an estimated 60,000 - 70,000 people have been forced to flee towards Mawasi.People in Gaza are exhausted, and they have nowhere to go. #CeasefireNow pic.twitter.com/rCbL2eAf95August 9, 2024
There was no immediate information from Gaza health authorities.
The Israeli military said in a statement its air force targeted a command and control centre where Hamas operatives were hiding.
The military said it had taken steps to reduce the risk of harming civilians, "including the use of precise munitions, aerial surveillance, and intelligence information".
It did not immediately comment on the casualty reports from Gaza.
The US, Egypt and Qatar are trying to revive Gaza ceasefire talks, scheduling a new round of negotiations for Thursday as fears grow of a broader conflict involving Iran and its Lebanese ally Hezbollah.
Teheran also backs Hamas.
Israeli tanks have returned to the southern Gaza city of Khan Younis, forcing families to evacuate along congested roadways as Palestinian fighters continue to attack Israeli troops from the ruins.
Workers have buried bodies returned by Israel in a cemetery in Khan Younis, Gaza Strip. (AP PHOTO)
Israeli planes carried out strikes across the enclave on Friday, killing at least 35 Palestinians, the Gaza health ministry said.
Thousands of people fled eastern Khan Younis in vehicles and on foot, belongings heaped on donkey carts and motorcycle rickshaws as they made their slow escape along congested roads.
In recent weeks, Israeli forces which swept into almost the entire Gaza Strip during 10 months of war, have been returning to the ruins of areas where they said they had defeated Hamas fighters, warning that they might regroup.
In the latest assault, the military dropped leaflets ordering residents and displaced people sheltering in eastern Khan Younis, Gaza's main southern city, to evacuate from an area that has already seen repeated waves of fighting.
Families packed into buses and cars, many seeking shelter in Al-Mawasi, a sandy stretch of ground along the coast, although some expressed fear over attacks there even though it was designated a safe zone by Israeli forces.
Later on Friday, an Israeli air strike killed six Palestinians in Al-Mawasi, medics said.
Another strike on a house nearby killed four people and wounded several others, they said.
Pursuant to the proposal by the US and the mediators, Israel will – on 15 August – send the negotiations team to a place to be determined in order to finalize the details of the implementation of the framework agreement.— Prime Minister of Israel (@IsraeliPM) August 9, 2024
The Israeli military said troops hit dozens of Hamas targets in Khan Younis and Rafah close to the Egyptian border, seizing arms depots, destroying infrastructure and killing dozens of fighters armed with weapons including rocket-propelled grenades.
The meeting called for Thursday to discuss a Gaza ceasefire and hostage release deal follows previous talks that have failed to yield a deal since a single week-long truce in November 2023.
Israel's prime minister's office said a delegation would be sent to the talks but declined to give further details.
A Hamas official told Reuters the group was "studying" the new offer for talks, refusing to elaborate.
The newly appointed overall leader of Hamas, Yahya Sinwar, is believed to be running the battle, possibly from the tunnels of Gaza.
Israel launched its assault on Gaza aiming to wipe out Hamas after the group's fighters attacked Israeli towns on October 7, killing 1200 people and capturing more than 250 hostages according to Israeli tallies.
Since then, Israel has killed almost 40,000 Palestinians in Gaza, according to figures from health officials in the enclave, who say thousands of others are feared dead under the rubble.