Troops shelled rebel positions in Aleppo on Sunday after a night of fierce fighting for control of Syria's second city where a fire tore through a historic souk, monitors said.
In Damascus province, soldiers backed by aerial firepower stormed the rebel stronghold of Harasta as regime forces carried out arrest raids in the town of Zabadani, said the Syrian Observatory for Human Rights.
Clashes were reported elsewhere in the northern province of Aleppo, where rebel mortar fire damaged two helicopters at the Al-Nairab military airport, said the group which relies on a network of activists on the ground.
The fighting was accompanied by intense overnight shelling that continued into the morning, destroying several houses and killing at least three people in Aleppo city, including two civilians and a rebel fighter, it said.
Aleppo, Syria's most populous city, has been the main battleground for the past two months of the country's 18-month conflict, and has been gripped by fighting on an unprecedented scale in recent days.
Much of the fighting has centred in and around the Old City, and this is believed to have sparked the fire in the centuries-old souk which destroyed many shops, said an AFP correspondent and the Observatory.
Elsewhere, troops trying to dislodge rebels fired heavy artillery into areas of the southern province of Daraa, central region of Hama and Idlib in the country's northwest, said the Observatory.
In the northeastern province of Hasakeh, the army fired on several houses, injuring several people, as security forces conducted arrest operations in the coastal city of Banias, it added.
Violence across Syria killed more than 118 people on Saturday -- 48 civilians, 41 soldiers and 29 rebels, the Observatory said, adding to its toll of over 30,000 killed since an anti-regime uprising erupted in March 2011.