A man gestures in front of the car in which three sons of Hamas leader Ismail Haniyeh were reportedly killed in an Israeli air strike in Al Shati camp, west of Gaza City on Wednesday. AFP

Hamas chief Ismail Haniyeh insisted that the death of three of his sons in an Israeli air strike would not influence truce talks in Gaza, as bombardments on Thursday rocked the Palestinian territory.

Israel confirmed the killings, which came as talks in Cairo for a temporary ceasefire and hostage release deal drag on without signs of a breakthrough.

Speaking to Qatari broadcaster Al Jazeera, Haniyeh suggested that the strike, which also killed four of his grandchildren, was an attempt to shift Hamas's negotiating stance.

"If they think that this will force Hamas to change its positions, they are delusional," he said.

US President Joe Biden said Hamas "needs to move" on the latest truce proposal, which the group has said it is studying.

Israel's main international ally the United States has also been ramping up pressure on Prime Minister Benjamin Netanyahu to agree to a truce, increase the amount of aid flowing into the besieged Gaza Strip and abandon plans to invade the southern city of Rafah.

Biden labelled Netanyahu's handling of the war a "mistake" in an interview broadcast on Tuesday, before warning on Wednesday that Israel has not allowed enough aid into the territory.

Despite calls for a ceasefire, Israel carried out strikes early Thursday in the Gaza Strip, particularly in the south of the territory, witnesses said.

Volunteers transport a body to a hospital after an Israeli strike in Rafah. AP

The war broke out with Hamas's October 7 attack against Israel, which resulted in the deaths of 1,170 people, mostly civilians, according to Israeli figures.

Palestinian fighters also took about 250 hostages, 129 of whom remain in Gaza, including 34 the Israeli army says are dead.

Israel's retaliatory offensive has killed at least 33,482 people in Gaza, mostly women and children, according to the Hamas-run territory's health ministry.

Hamas 'studying' truce

Talks mediated by the United States, Egypt and Qatar have been ongoing since Sunday.

Hamas spokesman in Doha Hossam Badran told AFP: "Hamas is studying the offer presented... It has not responded yet."

A framework being circulated would halt fighting for six weeks and see the exchange of about 40 hostages for hundreds of Palestinian prisoners.

Palestinians mourn over the bodies of their relatives in Gaza Strip on Wednesday. AP

Biden, speaking at a news conference on Wednesday, said: "It's now up to Hamas, they need to move on the proposal that's been made".

There has been a growing chorus of international criticism aimed at Israel's handling of the war and the paucity of aid entering the territory.

On Wednesday, Spanish Prime Minister Pedro Sanchez warned that what he called Israel's "disproportionate response" in Gaza risked "destabilising the Middle East, and as a consequence, the entire world".

Spain is among several Western nations, including Ireland and Australia, to have suggested they would recognise a Palestinian state in the near future as a starting point for wider peace talks.

Agence France-Presse