As international pressure mounted for a ceasefire after more than 10 months of war between Israel and Hamas in the Gaza Strip, US President Joe Biden said: "We are closer than we have ever been."

Washington has joined its European allies in pushing for a swift ceasefire in Gaza since the July 31 killing of Hamas political leader Ismail Haniyeh in an attack in Iran blamed on Israel prompted threats of retaliation and fears of a wider Middle East war.

Egyptian, Qatari and US mediators have been seeking to finalize details of a framework initially outlined by Biden in May, and which he said Israel had proposed.

But months of talks have so far failed to pin down the details of a truce and hostage release deal.

The mediators said that the two days of talks in Doha were "serious and constructive".

In a joint statement, they said the United States had presented a "bridging proposal" that sought to secure a rapid deal at a new round of talks in Cairo next week.

Hamas swiftly announced its opposition to what it called "new conditions" from Israel in the latest plan.

Israeli Prime Minister Benjamin Netanyahu meanwhile called on the mediators to put "pressure" on Hamas "to accept the May 27 principles", referring to Biden's framework.

An informed source told AFP that the conditions Hamas objected to included keeping Israeli troops inside Gaza along the territory's border with Egypt, veto rights for Israel on the Palestinian prisoners to be exchanged for Israeli hostages, and the ability to deport some prisoners rather than send them back to Gaza.

Qatar's lead mediator, Prime Minister Sheikh Mohammed bin Abdulrahman Al-Thani spoke with Iran's acting foreign minister Ali Bagheri to brief him about the talks, the foreign ministry in Doha said.

"During the call, they reviewed [...] the latest developments in the joint mediation efforts to end the war on the Strip, and stressed the need for calm and de-escalation in the region," the Qatari statement said.

Diplomatic pressure on Israel to agree a truce has increased in recent weeks.

Hamas officials, some analysts and protesters in Israel have accused Netanyahu of prolonging the war.

Ahead of a visit to Israel on Friday with French Foreign Minister Stephane Sejourne, British Foreign Secretary David Lammy said: "The risk of the situation spiraling out of control is rising." 

Britain's foreign ministry said the two ministers would "stress there is no time for delays or excuses from all parties on a ceasefire deal" in Gaza.

Israeli Foreign Minister Israel Katz told his visiting counterparts he expects foreign support "in attacking" Iran if it strikes Israel in revenge for Haniyeh's killing.

Sejourne replied that it would be "inappropriate" to discuss responding to any attack while diplomacy is in high gear to stop it happening.

As the Gaza truce talks drag on, bombs have continued to fall in the Palestinian territory.

Hamas's unprecedented October 7 attack on Israel triggered the war that resulted in the deaths of 1,198 people, mostly civilians, according to an AFP tally of Israeli official figures.

Militants also seized 251 hostages, 111 of whom are still held in Gaza, including 39 the military says are dead. More than 100 were freed during a one-week truce in November.

On Thursday, the toll from Israel's retaliatory military campaign in Gaza topped 40,000, according to the health ministry in Hamas-run Gaza, which does not provide a breakdown of civilian and militant casualties.

"Why did Netanyahu send a delegation to the talks while we are being killed here?" in Jabalia, Mohammed al-Balwi asked among the concrete debris left from a deadly air strike Thursday in north Gaza.