American forces killed an Islamic State (IS) group leader in an air strike in Syria, the U.S. military said on Friday.

The strike took place the previous day in Deir Ezzor province in eastern Syria, killing a leader known as "Abou Youssef" and another of the group's operatives, the U.S. Central Command (CENTCOM) said on social media.

The leaders of Turkey and Iran met in Cairo at a summit of eight Muslim-majority countries, in their first sit-down since the fall of Syrian president Bashar al-Assad.

The two countries were on opposite sides of Syria's long-running civil war, with Turkey historically backing Assad's opponents and Iran supporting his rule.

Ukrainian President Volodymyr Zelensky said Thursday he needed both Europe and the United States on board to secure a durable peace, as he huddled with EU leaders at their final summit before Donald Trump's inauguration.

Trump returns to the White House next month having pledged to bring a swift end to a conflict that NATO says has left more than one million dead and wounded since Russian President Vladimir Putin's 2022 invasion.

U.S. diplomats met with Syria's new ruler on Friday, an official told AFP, as outside powers seek assurances the country's Islamist-led authorities will be moderate and inclusive.

The ouster of former president Bashar al-Assad ended decades of abuses and years of civil war, but raised concerns over minorities and women's rights, as well as the future of the semi-autonomous Kurdish region.

U.N. Secretary-General Antonio Guterres said Thursday that there was a "flame of hope" in Syria following the fall of president Bashar al-Assad's regime but warned of significant challenges ahead.

He also underlined that Israel's widespread strikes on Syrian military infrastructure were "violations" of the country's sovereignty and called for them to cease.

Hundreds of Syrians protested Thursday in central Damascus calling for democracy and women's rights, more than a week after an Islamist-led rebel alliance ousted president Bashar al-Assad, AFP correspondents said.

"We want a democracy, not a religious state," men and women demonstrators chanted in central Damascus's Ummayad Square, as well as "Free, civil Syria" and "the Syrian people are one", while some protesters held signs including "No free nation without free women".

Russian President Vladimir Putin on Thursday urged Israel to remove its forces from the "territory of Syria".

"We hope that Israel will at some point leave the territory of Syria. But now it is bringing in additional troops," Putin said at his annual end-of-year press conference.

The Palestinian health ministry said Thursday that an Israeli air strike on a car killed four Palestinians and wounded three near the occupied West Bank city of Tulkarem.

The ministry announced that the Palestinians were killed "as a result of the (Israeli) bombing of a vehicle in Tulkarem camp", which the Israeli army did not immediately confirm to AFP.

Efforts to strike a Gaza truce and hostage release deal between Israel and Hamas have repeatedly failed over key stumbling blocks, but recent negotiations have raised hope of an agreement.

U.S. Secretary of State Antony Blinken said Wednesday he remained hopeful of reaching a ceasefire between Israel and Hamas in Gaza, after Washington expressed Tuesday "cautious optimism" on the possibility of an "imminent deal".

Turkish President Recep Tayyip Erdogan has said Turkey and Lebanon would work together on Syria after the overthrow of Bashar al-Assad by Islamist-led rebels.

"A new era has now begun in Syria. We agree that we must act together as two important neighbors of Syria," Erdogan told a news conference Wednesday, alongside Lebanese Prime Minister Najib Mikati.