An Israeli strike on a school sheltering the displaced in the Gaza Strip has killed at least 27 people, Palestinian medical officials say.

The Israeli military said it targeted militants hiding among civilians, without providing evidence.

Israel has continued to strike at what it says are militant targets across the Palestinian enclave even as attention has shifted to its war against Hezbollah in Lebanon and rising tensions with Iran. 

The military launched a large-scale air and ground operation against Hamas in northern Gaza earlier this week.

The Al-Aqsa Martyrs Hospital, where the bodies were brought on Thursday, said the strike in the central town of Deir al-Balah killed 27 people, including a child and seven women. 

It said several other people were wounded.

An Associated Press reporter saw ambulances streaming into the hospital and counted the bodies, many of which arrived in pieces.

"We appeal to the world. We are dying!" one man screamed. 

The Israeli military said it carried out a precise strike targeting a militant command and control centre inside the school. 

Israel has repeatedly attacked schools that were turned into shelters in Gaza, accusing militants of hiding out in them.

Witnesses who spoke on condition of anonymity for security reasons said the strike occurred while school managers were meeting with representatives of an aid group in a room usually used by Hamas-run police who provide security. 

They said there were no police in the room at the time.

The Hamas-run government operated a civilian police force numbering in the tens of thousands. 

They largely vanished from the streets after the start of the war as Israel targeted them with airstrikes, but plain-clothes Hamas security personnel still exert control over most areas.

Hamas has continued to launch attacks on Israeli forces and fire occasional rockets into Israel more than a year after its October 7 attack ignited the war.

Hamas-led militants stormed into Israel and rampaged through army bases and farming communities in that attack, killing some 1200 people, mostly civilians, and abducting about 250 others. 

They are still holding about 100 captives, a third of whom are believed to be dead.

Israel's offensive has killed more than 42,000 Palestinians, according to local health authorities, who do not say how many were fighters but say women and children make up more than half of the fatalities. 

The war has destroyed large areas of Gaza and displaced about 90 per cent of its population of 2.3 million people, often multiple times.