The US says "very serious" negotiations are taking place on a new Gaza ceasefire and release of more Israeli hostages, but prospects for a deal remain uncertain as Hamas insists it will not discuss anything less than a complete end to Israel's offensive in the Palestinian enclave.
Hamas leader Ismail Haniyeh visited Egypt on Wednesday for the first time in more than a month for discussions with Egyptian officials who are seeking to mediate another truce.
A source briefed on the negotiations said envoys were intensively discussing which of the hostages still held by Palestinian Islamist militants in Gaza could be freed in a new truce and which Palestinian prisoners Israel might release in return.
Islamic Jihad, a smaller Palestinian militant group that is also holding hostages in Gaza, said its leader would also visit Egypt to discuss a possible end to the conflict.
"These are very serious discussions and negotiations, and we hope that they lead somewhere," White House spokesman John Kirby told reporters aboard Air Force One.
But Taher Al-Nono, Haniyeh's media adviser, told Reuters that Hamas was not willing to discuss releasing more Israeli hostages until Israel ended its military campaign in Gaza and the volume of humanitarian aid to Palestinian civilians increased.
"The issue of prisoners can be negotiated after these two matters are achieved. We cannot talk about negotiations while Israel continues its aggression," Nono said.
Hamas rejects any further temporary pause in Israel's military campaign and says it will discuss only a permanent ceasefire.
Israel had insisted all remaining women and infirm men among the hostages be released, the source said.
Palestinians convicted of serious offences could be on the list of prisoners to be freed by Israel.
Israel launched its campaign in the Gaza Strip with the aim of annihilating Hamas after its fighters raided Israel on October 7.
They took some 240 hostages and killed 1200 people, according to Israel.
Since then, Israel has waged a massive ground and air assault on the seaside enclave.
Nearly 20,000 deaths have been confirmed by the Gazan health ministry.
International aid groups say Gaza's 2.3 million people have been driven to the brink of catastrophe by destruction that has driven 90 per cent of them from their homes and left many malnourished and gravely short of clean water and medical care.
US President Joe Biden on Wednesday said he did not expect a second Israel-Hamas hostage release deal to be struck soon, though he told reporters: "We're pushing."
Haniyeh's visit to Egypt was a rare personal intervention in diplomacy, something he has done in the past only when progress seemed likely.
He last travelled to Egypt in early November before the announcement of the only ceasefire in the Gaza war, a week-long pause that saw the release of about 110 of Hamas' hostages.
Israel has not commented publicly on the talks in Egypt, but it has ruled out a permanent ceasefire and says it will only agree to limited humanitarian pauses until Hamas is defeated.
Israeli Prime Minister Benjamin Netanyahu repeated that the war would end only with Hamas eradicated, all hostages freed and Gaza posing no more threat to Israel.
"Whoever thinks we will stop is detached from reality ... All Hamas terrorists, from the first to the last, are dead men walking," he said on Wednesday.
The US has stepped up calls for Israel to scale down its war into a focused campaign against Hamas leaders and end what Biden called "indiscriminate bombing" causing huge civilian casualties.
In a serious spillover, Yemen's Houthi forces have been firing missiles and drones at commercial shipping in the Red Sea to underline support from Iran's Arab militia proxies for the Palestinians against Israel, and the US this week set up a multinational force to ward off the attacks.
On Wednesday, the Houthis' leader warned they would strike US warships if their forces were targeted by Washington.
The United Nations Security Council was due to vote on Thursday on a bid to boost aid to the Gaza Strip after a delay at the request of the US, diplomats said.
Aid into Gaza has gradually increased after the opening of a second crossing into the enclave.
