The truce, announced by mediators Qatar and the United States on Wednesday, would begin on Sunday and involve the exchange of Israeli hostages for Palestinian prisoners, after which the terms of a permanent end to the war would be finalised.

However, the office of Prime Minister Benjamin Netanyahu said Thursday that Hamas had "reneged on parts of the agreement... in an effort to extort last-minute concessions".

It also said Israel's cabinet, which has yet to approve the agreement, "will not convene until the mediators notify Israel that Hamas has accepted all elements of the agreement".

An Israeli official later told AFP the cabinet was scheduled to meet Friday to decide on the deal.

Hamas political bureau member Sami Abu Zuhri, meanwhile, said there was "no basis" for Israel's accusations.

US Secretary of State Antony Blinken, who has been involved in months of mediation efforts, said he believed the ceasefire would go ahead on schedule.

"I am confident, and I fully expect that implementation will begin, as we said, on Sunday," he said.

The foreign ministry of fellow mediator Egypt said in a statement the ceasefire must "start without delay".

Gaza's civil defence agency said Israel pounded several areas of the territory after the deal was announced, killing at least 80 people and wounding hundreds.

The Israeli military said it had hit about 50 targets across Gaza since late Wednesday, targeting Palestinian militants.

Hamas's armed wing, the Ezzedine al-Qassam Brigades, warned that Israeli strikes were risking the lives of hostages due to be freed under the deal, and could turn their "freedom... into a tragedy".

The war was triggered by the October 7, 2023 Hamas attack on Israel, which resulted in the deaths of 1,210 people, mostly civilians, according to an AFP tally of official Israeli figures.

During the attack, the deadliest in Israeli history, Palestinian militants also took 251 people hostage, 94 of whom are still being held in Gaza, including 34 the Israeli military says are dead.

Israel's ensuing campaign has destroyed much of Gaza, killing 46,788 people, most of them civilians, according to figures from the Hamas-run territory's health ministry that the UN considers reliable.

- Mixed feelings -

The ceasefire agreement followed intensified efforts from mediators Qatar, Egypt and the United States, after months of fruitless negotiations to end the deadliest war in Gaza's history.

If finalised, it would pause hostilities one day before the inauguration of US President-elect Donald Trump.

Envoys from both the Trump team and the outgoing administration of President Joe Biden were present at the latest negotiations, with a senior Biden official saying the unlikely pairing had been a decisive factor in reaching the deal.

In Israel and Gaza, there were celebrations welcoming the truce deal, but also anguish.

Saeed Alloush, who lives in north Gaza, said he and his loved ones were "waiting for the truce and were happy", until overnight strikes killed many of his relatives.

"It was the happiest night since October 7" until "we received the news of the martyrdom of 40 people from the Alloush family", he said.

In Tel Aviv, pensioner Simon Patya said he felt "great joy" that some hostages would return alive, but also "great sorrow for those who are returning in bags, and that will be a very strong blow, morally".

Two far-right party leaders in Netanyahu's cabinet have publicly opposed the agreement.

Finance Minister Bezalel Smotrich said it was a "dangerous deal", while National Security Minister Itamar Ben Gvir called it "disastrous".

Israeli media said the government's ratification of the agreement may be delayed, in part, by disagreements within the ruling coalition.

Qatari Prime Minister Sheikh Mohammed bin Abdulrahman bin Jassim Al-Thani, announcing the agreement on Wednesday, said an initial 42-day ceasefire would see 33 hostages released, including women, "children, elderly people, as well as civilian ill people and wounded".

Also in the first phase, Israeli forces would withdraw from Gaza's densely populated areas and allow displaced Palestinians to return "to their residences", he said.

- Aid needed -

Announcing the deal from the White House, Biden said he was "deeply satisfied this day has come".

He added that the second phase of the agreement could bring a "permanent end to the war".

Biden said the deal would "surge much needed humanitarian assistance to Palestinian civilians, and reunite the hostages with their families".

Egyptian President Abdel Fattah al-Sisi also underscored the "importance of accelerating the entry of urgent humanitarian aid" into Gaza.

Cairo said it was ready to host an international conference on reconstruction of the Gaza Strip, where the United Nations has said it would take more than a decade to rebuild civilian infrastructure.

The World Health Organization's representative in the Palestinian territories, Rik Peeperkorn, said Thursday that at least $10 billion would probably be needed over the next five to seven years to rebuild Gaza's devastated health system alone.

The UN Palestinian refugee agency UNRWA, facing an Israeli ban on its activities set to start later this month, welcomed the ceasefire deal.

"What's needed is rapid, unhindered and uninterrupted humanitarian access and supplies to respond to the tremendous suffering caused by this war," UNRWA head Philippe Lazzarini wrote on X.

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