Syria conflict: IS-rebel clashes 'leave 40 dead'
More than 40 people are reported to have been killed in clashes between Syrian Islamist rebels and Islamic State militants north of Damascus.
The Syrian Observatory for Human Rights said the fighting in the eastern Qalamoun mountains had left 30 rebels and 12 jihadists dead since Tuesday.
The area is important because it straddles rebel weapons supply routes.
IS had already cut off one route and aimed to take more to "suffocate" the rebels, the Syrian Observatory said.
The western part of the Qalamoun mountains, which borders Lebanon, is mostly controlled by the government and fighters from the allied Lebanese Shia Islamist movement, Hezbollah.
Meanwhile, 13 civilians have been killed in the north-western province of Idlib.
Activists reported that a government air raid on the town of Maarat al-Numan had left a man and five children dead. They also said rebel shelling on government-held Jisr al-Shughour had killed seven others, including a couple and their four children.
The city of Idlib was overrun by al-Qaeda's affiliate in Syria, al-Nusra Front, and allied rebel groups last month. Since then, government forces have been trying to protect their supply route between Jisr al-Shughour and Ariha, to the east.