France has condemned violence in Syria targeting "civilians because of their faith, and prisoners", as a war monitor said more than 500 Alawites have been killed in recent days.

A French foreign ministry statement called on Syria's new authorities "to ensure that independent investigations can shed light on these crimes, and that the perpetrators are sentenced".

The leaders of Syria's three main Christian churches have issued a joint statement condemning "massacres targeting innocent civilians", following reports of mass killings of Alawite civilians by the security forces.

Syrian President Ahmed al-Sharaa called for national unity and peace on Sunday, after more than 1,000 people were reportedly killed in coastal Syria in the worst clashes since the overthrow of Bashar al-Assad.

The violence erupted on Thursday between the new security forces and loyalists of the former government along the Mediterranean coast in the heartland of the Alawite minority to which Assad belonged, before escalating into massacres against Alawite civilians that left hundreds dead.

Yemen's Iran-backed Houthis will resume attacks on Israeli shipping if aid supplies to Gaza do not resume in four days, the rebels' leader said on Friday.

"If the Israeli enemy continues after the first four days to prevent the entry of aid into the Gaza Strip... then we will resume our naval operations against the Israeli enemy," Abdulmalik al-Houthi said in a televised address.

Syria's leader Ahmed al-Sharaa has urged insurgents from ousted president Bashar al-Assad's Alawite minority to lay down their arms and surrender after the fiercest attacks on the war-torn country's new rulers yet.

A Syria war monitor reported on Saturday that more than 300 Alawite civilians have been killed in recent days by the security forces and their allies, as authorities clash with militants loyal to the former government of Bashar al-Assad.

Restoring security has been one of the most complex tasks for Syria's new authorities, installed after Islamist-led forces ousted Assad in a lightning offensive in December.

A high-level Hamas delegation arrived in Cairo to advance efforts on a fragile ceasefire in Gaza, which has largely paused hostilities with Israel, two senior Hamas officials told AFP Friday.

"The delegation will meet with Egyptian officials on Saturday to discuss the latest developments, assess progress in implementing the ceasefire agreement, and address matters related to launching the second phase of the deal," one official said.

Sudan filed a case at the top United Nations court accusing the United Arab Emirates of breaching the genocide convention by arming and funding the rebel paramilitary group Rapid Support Forces in Sudan's deadly war, the court announced Thursday. The UAE called the filing a publicity stunt and said it would seek to have the case dismissed.

The International Court of Justice said Sudan's case, filed Wednesday, concerns acts allegedly perpetrated by the Rapid Support Forces and allied militias including "genocide, murder, theft of property, rape, forcible displacement, trespassing, vandalism of public properties, and violation of human rights" targeting the Masalit people.

The Muslim world will be asked to throw its weight behind an Arab counter-plan to U.S. President Donald Trump's widely condemned proposal to take over war-torn Gaza at an emergency meeting on Friday.

Foreign ministers from the 57-member Organization for Islamic Cooperation (OIC) will meet at its headquarters in Jeddah, Saudi Arabia, three days after the Arab League endorsed Egypt's alternative plan for Gaza.

Jailed Egyptian-British activist Alaa Abdel Fattah began a hunger strike at the start of the month after his mother was hospitalized more than 150 days into her own hunger strike, his family said on Friday.

He began refusing food at the Wadi al-Natroun prison "on Saturday March 1 after hearing news that his mother had been hospitalized" in London, where she has been on hunger strike to put pressure on the British government to secure his release.