Palestinian leaders on Wednesday denounced Israel's refusal to negotiate with Palestinians on hunger strike in Israeli jails, warning of a "new intifada" if any of them die.

A bomb killed six people and wounded more than 30 in Syria's second city Aleppo on Wednesday, state television reported. 

The blast hit the southwestern neighbourhood of Salaheddin, which was once on the front line between rebels and government forces before the army retook full control of the city in December. 

Two strikes apparently carried out by US drones killed five suspected al-Qaida members in Yemen overnight, military sources said on Wednesday.

Evacuations of thousands of besieged Syrians resumed on Wednesday with tight security in place after a weekend bombing against those leaving government-held areas killed dozens, including nearly 70 children. 

A large convoy of buses set out from the government-held towns of Fuaa and Kafraya in Idlib province, carrying 3,000 people to the rebel-held transit point of Rashidin near Aleppo, an AFP correspondent said.

A policeman was killed and three others wounded Tuesday when gunmen opened fire on a checkpoint near St Catherine's monastery in Egypt's Sinai, the interior ministry said, in an attack claimed by Islamic State jihadists.

"A number of gunmen... facing one of the checkpoints on the road to St Catherine's in south Sinai shot at security forces at the checkpoint," the interior ministry said in a statement on its Facebook page.

Egyptian police on Tuesday arrested a man wanted for alleged involvement in twin church bombings this month claimed by the Islamic State group, an official said.

The U.S.-backed Kurdish-Arab force leading the fight for the Islamic State group's Syrian bastion Raqa announced Tuesday the creation of a "civilian council" to administer the city after its capture.

Twelve Saudi soldiers, including four officers, were killed on Tuesday when their helicopter went down in Yemen, the Arab coalition fighting Yemeni rebels said in a statement.

The Saudi Black Hawk "fell during operations in the province of Marib" east of Sanaa, the coalition said in a statement carried by SPA state news agency, without clarifying the reason.

Can threatening war crimes charges persuade Syrian President Bashar al-Assad to leave power? What about guaranteeing his safety in exile? These long-shot proposals are at the center of the Trump administration's new effort to resolve Syria's six-year civil war.

Though still evolving, President Donald Trump's plans for Syria have come into clearer view since he ordered cruise missiles fired on a Syrian air base to punish Assad for a chemical weapons attack. The strategy breaks down into three basic phases: defeating the Islamic State group, restoring stability in Syria region-by-region and securing a political transition in which Assad ultimately steps down.

Air strikes by the U.S.-led coalition fighting the Islamic State group killed 20 civilians in Syria's eastern Deir Ezzor province, a monitor said on Tuesday.