Qatar and the United States announced Wednesday a ceasefire and hostage-release deal between Israel and Hamas, adding that they hoped it would pave the way for a permanent end to the war in Gaza.

After mediators said a deal had been reached, the office of Israeli Prime Minister Benjamin Netanyahu said the "final details" were being worked on.

Netanyahu spoke with US President Joe Biden and President-elect Donald Trump on Wednesday to thank them for their help securing the agreement, his office said.

Israelis expressed both joy and apprehension at the announcement of a Gaza ceasefire and hostage exchange deal on Wednesday, fearing that not all those held captive would come home.

"On one hand, of course, I'm very happy, but I'm also preoccupied because I want to see the deal continue until the last hostage is back at home, in his bed, the living and the dead", Ornit Barak, 59, told AFP.

US President Joe Biden announced Wednesday a "full and complete" ceasefire between Israel and Hamas in the first part of their peace accord, and said he had acted as "one team" with incoming leader Donald Trump.

Speaking at the White House just days before he leaves office, a visibly relieved Biden said the negotiations to halt the Gaza conflict had been some of the "toughest" of his career.

"I'm deeply satisfied this day has come, finally come," Biden said in a televised statement.

Crowds of Gazans chanted and embraced on Wednesday as news spread that a ceasefire and hostage release deal had been reached between Israel and Hamas aimed at ending more than 15 months of war in the Palestinian territory.

After a US official and a source close to the negotiations first revealed the agreement, Israel cautioned that several points "remain unresolved" that it hoped would be addressed.

But celebrations were already underway in Gaza, where AFP journalists saw crowds of people hugging and taking photos to mark the announcement.

Qatar's prime minister announced that Israel and Hamas had agreed Wednesday to a ceasefire and the release of hostages held in Gaza, adding he hoped the deal would pave the way for a permanent end to the fighting.

After mediators earlier said a deal had been reached, the office of Israeli Prime Minister Benjamin Netanyahu cautioned that some issues in the framework remained "unresolved", though it hoped the "details will be finalised tonight".

United Nations rights chief Volker Turk on Wednesday said transitional justice was "crucial" for Syria after the fall of Bashar al-Assad, during the first-ever visit by someone in his post to the country.

Since Islamist-led rebels seized Damascus last month, the United Nations has called for Assad and others to be held accountable for the crimes committed during more than 13 years of civil war.

"Transitional justice is crucial as Syria moves forward," the UN high commissioner for human rights said at a press conference in Damascus.

Survivors of sexual violence emerging from Syria's prisons need reparations, urged Nobel laureate Denis Mukwege, renowned for his work with victims of sexual violence during conflict.

Since the dramatic fall of president Bashar al-Assad last month, the rebels who toppled the longtime strongman have liberated thousands of prisoners held in Assad's jails.

Congolese gynaecologist Mukwege, who has spent his life dealing with sexual violence committed during wartime, described the shocking abuses committed there in an interview with AFP this week.

Gaza's civil defence agency said on Wednesday that Israeli strikes killed at least 27 people, as the military issued new evacuation calls in northern areas of the Palestinian territory.

The latest Israeli strikes come as truce mediator Qatar said negotiations for a ceasefire and hostage release deal in Gaza were in their "final stages".

The civil defence agency said in a statement that 11 bodies were brought to the Al-Aqsa Martyrs Hospital in the central Gaza Strip, after Israel struck a family home in Deir el-Balah city during the night.

Iraq and British oil giant BP are set to finalise a deal by early February to develop four oil fields in Kirkuk and curb gas flaring, Iraqi authorities announced Wednesday.

The mega-project in northern Iraq will include plans to recover flared gas to boost the country's electricity production, they said.

Gas flaring refers to the polluting practice of burning off excess gas during oil drilling. It is cheaper than capturing the associated gas.

In a Damascus courtyard, Syrian activists brainstormed strategies to ensure their country does not return to authoritarianism, in a scene unimaginable under president Bashar al-Assad's rule.

Since Islamist-led rebels ousted the longtime ruler last month, the Syrian capital's public spaces have been abuzz with previously banned civil society meetings.

Exiled activists have returned to the country for the first time in years, often leading to moving reunions with friends who stayed behind throughout the civil war.