Doubts were growing on Monday about a plan for a Gaza ceasefire and hostage release deal outlined by U.S. President Joe Biden as heavy fighting raged for a third day since his White House address.

Biden on Friday presented what he labelled an Israeli three-phase plan that would end the bloody conflict, free all hostages and lead to the reconstruction of the devastated Palestinian territory without Hamas in power.

At least 12 pro-regime fighters were killed in an overnight Israeli strike that targeted a factory near Aleppo in the north of Syria, an NGO reported early Monday.

"Twelve pro-Iranian fighters of Syrian and foreign nationalities were killed, according to an initial tally, in an Israeli air strike on a position in the town of Hayyan, north of Aleppo, setting off strong explosions in a factory," the Syrian Observatory for Human Rights said.

Israel's prime minister faced growing pressure Saturday after U.S. President Joe Biden announced a proposed agreement to end the fighting in Gaza, with many Israelis urging Benjamin Netanyahu to embrace the deal but far-right allies threatening to collapse his government if he does.

Netanyahu called a permanent cease-fire in Gaza a "nonstarter" until long-standing conditions for ending the war are met, appearing to undermine the proposal that Biden described as an Israeli one.

Qatari, Egyptian and U.S. mediators have called on Israel and Hamas to "finalise" the truce deal outlined by US President Joe Biden, as Israeli forces pounded Rafah in southern Gaza.

Fighting has raged in the besieged Gaza Strip since Biden said Israel was offering a new roadmap towards a full ceasefire.

Congressional leaders have invited Israeli Prime Minister Benjamin Netanyahu to deliver an address a the Capitol, a show of wartime support for the longtime ally despite mounting political divisions over Israel's military assault on Gaza.

The invitation from House Speaker Mike Johnson, a Republican, and Senate Majority Leader Chuck Schumer, a Democrat, along with Senate Republican leader Mitch McConnell and House Democratic leader Hakeem Jeffries, has been in the works for some time. No date for the speech was set.

U.S. President Joe Biden overnight said that Israel has offered a new roadmap towards a permanent peace in Gaza, urging Hamas to accept the surprise deal as it was "time for this war to end."

In his first major address outlining a solution to the conflict, Biden said the three-phase proposal starts with a six-week complete ceasefire that would see Israeli forces withdraw from all populated areas of Gaza.

The humanitarian aid allowed into the Gaza Strip is not getting to civilians in need, the United Nations said Friday, urging Israel to fulfil its legal obligations.

"The aid that is getting in is not getting to the people, and that's a major problem," Jens Laerke, spokesman for the U.N. humanitarian agency OCHA, told a media briefing in Geneva.

Yemen's Houthi rebels on Friday threatened to escalate attacks on shipping in response to overnight strikes by United States and Britain, which Houthi media said had killed 16 people.

"The American-British aggression will not prevent us from continuing our military operations in support of Palestine," Huthi official Mohammed Al-Bukhaiti said on social media platform X, adding the rebels would "meet escalation with escalation".

Spain rejects "restrictions" that Israel plans to impose on the activities of its consulate in Jerusalem in response to Madrid's recognition of a Palestinian state, Spanish Foreign Minister Jose Manuel Albares said Friday.

"This morning we sent a note verbale to the Israeli government in which we reject any restriction on the normal activity of the Spanish consulate general in Jerusalem, as its status is guaranteed by international law," he said during an interview with radio Onda Cero.

Israeli War Cabinet member Benny Gantz’s centrist party has called for a vote to dissolve the parliament in an attempt to force early elections.

Thursday's announcement deepens a divide in Israel’s leadership more than seven months into a war. But it appears unlikely to threaten the current parliament. Even to put the request on the agenda requires majority consent from parliament, which would need at least five members of the governing coalition to defect and vote in favor.