At least 17 Palestinians, including children, were killed on Thursday in an Israeli strike on a school in Nuseirat camp in the central part of the Gaza Strip, where people displaced by the fighting were sheltering, Nuseirat's Al-Awda hospital said.

The Israeli military said it had hit a Hamas command and control centre embedded in a compound formerly used as a school in Nuseirat.

Hopes that the killing of Hamas leader Yahya Sinwar might provide an opening for an end to the fighting have so far been disappointed despite an international chorus urging Israel to use the opportunity.

In the northern section of the enclave, where the area around the town of Jabalia has been the target of a weeks-long operation, the military said it had evacuated large numbers of people and detained more than 200 suspected militants.

"Instead of achieving a ceasefire, war has restarted in northern Gaza. We are being besieged, starved, and hunted by the occupation from the air and from tanks," one Jabalia resident told Reuters via a chat app.

On Thursday, medics at the Indonesian Hospital, one of three facilities still operating in the area, said one of their colleagues was killed by Israeli fire and another detained on his way to work.

Health officials at the three hospitals, which say they have run out of medical, food and fuel supplies, refused Israeli orders to evacuate the facilities or leave patients unattended.

The Civil Emergency Service said Israeli attacks on their staff caused a suspension in their operations. Three of their men were wounded and another five were arrested by the army while their only fire truck was bombed by a tank.

Speaking at a new conference on Thursday, the rescue service spokesman said people in those areas had been left "without humanitarian, medical or rescue services".

The operation in the north has fuelled fears among Palestinians that Israeli forces are clearing the area in order to create an uninhabited buffer zone for the military after the war or to pave the way for the return of settlers who pulled out of Gaza in 2005.

Israel has denied such plans and accuses Hamas of hindering the evacuation of civilians to provide cover for its own forces, which Hamas, in turn, denies.

As the war moves into its second year, the death toll from the Israeli campaign in Gaza is approaching 43,000, with the densely populated enclave in ruins and almost all of its population displaced.

Israel, which launched the campaign in retaliation for the Hamas-led attack on Israel last year which killed some 1,200 people and saw more than 250 hostages taken to Gaza, has said it will continue until Hamas is dismantled completely as a military and governing power and the hostages return.

But it has not articulated any clear plan for Gaza's future after the war and international efforts to agree a ceasefire appear to have stalled.

Hamas, which has yet to name a successsor to Sinwar, said delegations were visiting Turkey, Qatar and Russia as well as being in touch with Egypt, the United Nations and Iran.