American, Israeli and Hamas negotiators are expected in Cairo over the weekend in a renewed push for a ceasefire and hostage release deal in a war that reaches the half-year mark on Sunday.

Ahead of the talks Hamas confirmed its core demands -- a complete ceasefire in Gaza and withdrawal of Israeli forces.

The ceasefire attempt comes after Israel's military made a rare admission of wrongdoing and said it was firing two officers over the killing of seven aid workers in Gaza where humanitarians say famine is imminent.

The admission did not quell calls for an independent probe, however.

The deaths of the workers from US-based World Central Kitchen (WCK) on April 1 led to a tense call between US President Joe Biden and Israel's Prime Minister Benjamin Netanyahu.

Biden urged an "immediate ceasefire" and for the first time hinted at conditioning US support for Israel on curtailing the killing of civilians and improving humanitarian conditions.

The bloodiest-ever Gaza war began on October 7 with an unprecedented attack from Gaza by Hamas militants resulting in the death of 1,170 people in southern Israel, mostly civilians, Israeli figures show.

Palestinian militants also took around 250 Israeli and foreign hostages, about 130 of whom remain in Gaza, including more than 30 the army says are dead.

Vowing to destroy Hamas, Israel has relentlessly bombarded the territory, killing at least 33,137 people, mostly women and children, according to the health ministry in the Hamas-run territory.

- Iran vows revenge -

The UN humanitarian chief Martin Griffiths decried Israel's war against Hamas and called for a "collective determination that there be a reckoning for this betrayal of humanity".

Fears that the war could spread intensified after Iran vowed retaliation after seven Revolutionary Guards were killed in an air strike Monday on the consular annex of its embassy in Damascus.

Ahead of the weekend talks, Biden wrote to the leaders of Egypt and Qatar urging them to secure commitments from Hamas to "agree to and abide by a deal", a senior administration official told AFP.

Stop-start talks have made no headway since a week-long truce in November saw some hostages exchanged for Palestinian prisoners detained by Israel.

The White House confirmed negotiations would occur this weekend in Cairo, and Hamas said its delegation would head there on Sunday.

But Hamas also restated its key demands.

"Hamas confirms its adherence to the position it presented on March 14 ... and we will not back down from this position," a statement said.

"The demands ... are complete ceasefire, withdrawal of the occupation forces from Gaza, the return of the displaced to their residential areas, freedom of movement of the people, offering them aid and shelter, and a serious hostage exchange deal," it said.

Biden's Thursday call with Netanyahu included discussions on "empowering his negotiators" to reach a deal, National Security Council spokesman John Kirby said.

Washington blames the lack of a deal on Hamas's refusal to release sick and other vulnerable hostages. Qatar has said Israeli objections to the return of displaced Gazans are the main holdup.

Biden is under pressure over massive US military aid to Israel which, so far, Washington has not leveraged despite increasingly critical comments about its conduct of the war.

UN agencies have accused Israel of blocking aid, but Israel blames shortages on aid groups' inability to distribute supplies once they get in.

The Israeli military announced it was firing two officers after finding a series of errors led to the drone strikes that killed the WCK workers.

WCK said its Gaza operations remain suspended after the attack, while other global aid groups said relief work in the territory has become almost impossible.

- 'Criminal' -

The army said a commander "mistakenly assumed" Hamas had seized the aid vehicles, which were moving at night.

Australia's Foreign Minister Penny Wong said Saturday Canberra had "not yet received sufficient information" from Israel about the death of Lalzawmi "Zomi" Frankcom and the other aid workers.

"It cannot be brushed aside and it cannot be covered over," Wong said.

WCK said Israel "cannot credibly investigate its own failure in Gaza" and said its staff were attacked despite having "followed all proper communications procedures".

Britain called for a "wholly independent review", while Poland sought a "criminal" probe.

Hours after Biden and Netanyahu spoke, Israel announced it would allow "temporary" aid deliveries through Israel's Ashdod port and the Erez border crossing.

UN chief Antonio Guterres called for a "paradigm shift" rather than "scattered measures".

- 'Dying from hunger' -

Mahmud Bassal, spokesman for Gaza's Civil Defence agency, told AFP Saturday aid reaching Gaza is "absolutely not sufficient" for its 2.4 million people, with basic necessities "extremely scarce" particularly in the north.

"Children are dying from hunger" there, he said.

Around 1.5 million Gazans are sheltering in the territory's far south, in Rafah.

"We are ordinary citizens and human beings," Siham Achur, 50, said in the tent that is now her family's home. "Why did they bomb our house?"

They had lived in Khan Yunis for 30 years, Achur said, but those memories "have become dust".

On Saturday, Israel's military said warplanes had killed Akram Salamah, a "senior" militant it said held several positions including Hamas's deputy chief for Khan Yunis.

Troops also recovered from Khan Yunis the body of Elad Katzir, who was abducted on October 7 and "murdered in captivity" by Islamic Jihad, a group fighting alongside Hamas, the army said.

His sister Carmit Palty Katzir on Facebook blamed the Israeli authorities for Elad's death, saying he would have returned alive had the authorities agreed to a new truce.

Israel's military has paused leave for combat units and reinforced "defence systems" since the Iranian consulate strike.

Iranian army chief Mohammad Bagheri on Saturday became the latest Iranian leader to vow retaliation.