Simmering hostility between Syria’s mainstream rebels and jihadists has erupted into naked violence, with a Free Syrian Army commander in the coastal province of Latakia being shot dead by an Al-Qaeda front group.

Kamal Hamami — better known by his nom-de-guerre Abu Bassir al-Jeblawi — was killed on Thursday by fighters of the Islamic State of Iraq and Syria (ISIS), one of the main jihadist groups operating in Syria, said witnesses and a monitoring group.

The killing follows months of tension between the mainstream, Arab and Western-backed rebel Free Syrian Army (FSA) and jihadist groups affiliated to Al-Qaeda, most of whose fighters are non-Syrian.

A rebel allied to Abu Bassir said via Facebook he had witnessed what he said was a cold-blooded shooting at an ISIS checkpoint when the rebel chief was on his way to visit fellow fighters at the front.

AFP journalists met with Abu Bassir twice earlier this year.

While the FSA is fighting to overthrow the Assad regime, the jihadist groups are intent on installing an Islamic caliphate in Syria.