Beirut: Two car bombs hit a rebel-held border post in the northwest Syrian province of Idlib on Monday, opposition activists and fighters said, killing at least 10 people and closing the frontier.

The Bab Al Hawa crossing is held by a rebel alliance called the Islamic Front, which have been fighting with the Al Qaida-linked Islamic State in Iraq and the Levant (Isil), a small but powerful affiliate of Al Qaida with a core of foreign fighters.

It was not immediately clear who planted the bombs. The attack occurred a few days after a car bomb that killed 26 in the eastern city of Jarablus and which activists blamed on Isil.

The infighting has sparked the bloodiest internecine clashes in the history of Syria’s nearly 3-year-old uprising, with more than 1,000 rebels killed, weakening the rebel campaign to topple President Bashar Al Assad.

Syrian rebel fighters in Bab Al Hawa said that at least 10 people had been killed and the border was shut on the Turkish side. A Syrian activist at Bab Al Hawa said that the two car bombs exploded within 10 minutes of each other.

The governor’s office in neighbouring Turkish Hatay province said the explosion was on the Syrian side of the border. Its press spokesman Cahit Dogan said there were no reports of damage or injuries on the Turkish side.