Fierce clashes erupted overnight as Syrian forces hammered rebel positions around Damascus with artillery and air strikes, as part of an offensive aimed at securing the capital, a watchdog said Sunday.

The fighting broke out in Irbin, a town east of Damascus, as troops also shelled Zabadani to the northwest of the capital and the village of Mliha, leaving many people wounded, said the Syrian Observatory for Human Rights.

Mliha, southeast of Damascus, is located in the region of Eastern Ghouta, where troops have launched a drive to secure the airport highway.

Forces loyal to President Bashar al-Assad have been trying to establish a secure perimeter around Damascus at all costs, turning the region into one of the main battlegrounds in the country's 20-month conflict.

Analysts say the objective of the military campaign is to put the regime in a position to negotiate a way out of the conflict that the Observatory says has cost more than 41,000 lives since March 2011.

In the north, the air force bombed the province of Aleppo, where ground troops have been locked in street fighting with rebels in Aleppo city for more than four months, said the watchdog.

The Observatory, which relies on a network of activists and medics for its information, said the regime also shelled the provinces of Daraa in the south and Homs in central Syria and Idlib in the northwest.

The Britain-based human rights monitor put Saturday's death toll from violence across the country at 182 -- 76 rebel fighters, 68 civilians and 38 soldiers.