Syria rebels, jihadists fight in northwest FIGHTERS of the mainstream rebel Free Syrian Army are battling jihadists from an al-Qaeda affiliated group trying to seize their weapons in the northwest. Tensions have been mounting between the FSA and the jihadist Islamic State of Iraq and Syria and boiled over after ISIS fighters shot dead an FSA commander on Thursday. Saturday's clashes erupted at dawn near Ras al-Hosn, in the north of Idlib province, when "ISIS fighters tried to seize weapons stored in Free Syrian Army depots," said Rami Abdel Rahman, director of the Syrian Observatory for Human Rights. Mainstream rebel fighters and jihadist groups such as ISIS and Al-Nusra Front, whose ranks include non-Syrian fighters, have clashed repeatedly in recent weeks. On Thursday, ISIS fighters killed FSA commander Kamal Hamami - better known by his nom-de-guerre Abu Bassir al-Jeblawi - at a checkpoint in the coastal province of Latakia, an incident expected to further rachet tensions. Idlib province, in Syria's northwest, has already seen clashes between mainstream rebels and jihadists. Late last week, dozens of FSA fighters were killed in a battle against ISIS, according to the Observatory. The FSA battalion chief there was beheaded by ISIS and his brother slaughtered, the group reported. In other violence on Saturday, rebels and regime forces fought pitched battles as regular troops tried to re-open a highway between Latakia and the northern city of Aleppo much needed as a supply route. Meanwhile, Aleppo residents protested for the second time this week against the rebel siege of regime-held districts in Syria's second city, where food shortages are mounting.