A regime advance on the town of al-Rayhan was repelled by rebel factions in eastern Ghouta in Damascus, while a Syrian army tank was destroyed in the attack.

Fighting also broke out in Khan al-Sheikh farms in the Damascus suburbs following regime airstrikes, The New Arab correspondent reported.

The area came under heavy bombardment but there were no reports of civilian losses.

Separately, the Syrian Observatory for Human Rights said at least four civilians were killed in airstrikes on Khan Shaykhun in the Idlib province north of Damascus.

"Helicopters dropped several barrel bombs on areas in the city of Khan Shaykhun south of Idlib province," the Observatory reported. "They targeted a fuel station and other areas in the city, resulting in break out of fires.

"Four people were killed and many more injured," the Observatory said, adding that the death toll was expected to rise due to the critical condition of some of the wounded.

A video of the attack circulated on social media showing the flames that engulfed the petrol station at Khan Shaykhun.

The Idlib province has come under intensified bombardment in recent weeks, including airstrikes targeting schools.

Last month, 35 people were killed air raids which struck a school complex in the village of Hass as children gathered outside preparing to return home.

Twenty-two children were among the dead in what UNICEF dubbed as the deadliest attack on a school since Syria's civil war began nearly six years ago.