Fierce battles and army shelling in and near Damascus on Tuesday killed at least 41 people, mostly civilians, a watchdog said, as warplanes launched more air raids on a town on the Turkish border.

A car bomb, meanwhile, struck the town of Ain al-Fijeh, west of the capital, "injuring a number of people and causing widespread material damage," said Syrian state television.

The Britain-based Syrian Observatory for Human Rights also reported the car bomb, but neither source gave details on casualties.

Fighting in the Eastern Ghuta area, east of the capital, cost the lives of at least 10 soldiers and a rebel, after rebel forces attacked public buildings in the area, the Syrian Observatory said.

The army used tanks to shell several towns east of Damascus, including Harasta, Zabadani and Irbin, killing at least seven civilians including an unknown number of women and children, the Observatory said.

In the capital itself, fighting broke out in the southern district of Tadamun, scene of intermittent clashes since mid-summer, state television and the Observatory said.

"Several army units are fighting with armed terrorist groups near the Othman mosque in the neighbourhood of Tadamun," said state television.

The Syrian Observatory also reported fresh air raids on Ras al-Ain, in northeastern Syria on the border with Turkey, and said 1,000 government troops had been sent to the town.

Air strikes have sent a new wave of civilians pouring into Turkey, adding to the 9,000 refugees who fled late last week when rebels overran the town, an AFP photographer said.

"Ras al-Ain is deserted now, it is a ghost town," said the Observatory.

In other violence, the army shelled rebel positions in the southern province of Daraa, in the central province of Homs, in Idlib in the northwest and in the northern city of Aleppo, said the Observatory.

At least 63 people were killed on Tuesday across Syria -- 29 civilians, 11 soldiers and 23 rebels -- said the Observatory, which relies for its information on a network of activists, lawyers and medics.

Among those killed was Abdel Razzaq al-Yusef a transport official assassinated by unidentified armed men in the northwestern province of Idlib, said the Observatory.

The watchdog has given an overall death toll of more than 37,000 since the anti-regime revolt broke out in March 2011.