The son of a Syrian archeologist who was beheaded by Islamic State group jihadists in ancient Palmyra is on a mission to give his father a "dignified" burial near the world heritage site.

Syrian President Bashar Assad has said that he is willing to hold early presidential elections if the Syrian people want them, in remarks released Thursday.

Syrian government air strikes killed at least 23 people including four children Thursday in the worst ceasefire violation yet in a key rebel bastion east of the capital, a monitoring group said.

Saudi Arabia executed a citizen on Thursday convicted of the murder of a compatriot, raising to 82 the number of death sentences the ultra-conservative kingdom has carried out this year.

Mohammed al-Khaweir al-Qahtani was found guilty of shooting dead Hussein al-Shayeb al-Qahtani following a dispute, the interior ministry said.

Israeli authorities overnight demolished the home of a Palestinian killed after fatally stabbing a Jewish settler in the West Bank city of Hebron, the Israeli army and Palestinian sources said on Thursday.

Israel regularly demolishes Palestinian attackers' homes in a bid to deter violence, but human rights activists say it amounts to collective punishment, forcing relatives to suffer for the acts of others.

A drone strike near the Islamic State group's de facto Syrian capital Raqa killed a jihadist commander heading to Aleppo province on orders from the organisation's chief, a monitoring group said Thursday.

His death is the latest in a series of blows to the jihadist group in recent weeks, and comes days after Russian-backed Syrian government forces recaptured the ancient city of Palmyra from its grip.

Yemeni rebels have mounted a deadly counterattack against government troops advancing down the Red Sea coast from the Saudi border ahead of a planned ceasefire next month, military sources said on Thursday.

The rebels and their allies surrounded a government force that was attempting to recapture the coastal town of Midi and killed 45 loyalist troops on Tuesday and Wednesday, the sources said.

Libya's unity government was trying to assert its authority in Tripoli Thursday after the new prime minister-designate's sudden arrival in the capital sparked tensions.

Fayez al-Sarraj's arrival at a naval base on Wednesday drew fury from the militia-backed authority in charge of Tripoli, which demanded he leave or surrender.

A border guard was injured late Wednesday in an ambush by more than a dozen "terrorists" in the Kasserine region near Tunisia's frontier with Algeria, the interior ministry in Tunis said.

"A group composed of around 15 terrorists ambushed a border guard vehicle and opened fire near Feriana," the ministry said in a statement.

Thousands of Palestinians and Arab Israelis gathered on Wednesday to commemorate the 40th anniversary of "Land Day" marking the killing of six Arab Israelis protesting plans to confiscate Arab land.