Syrian forces bombarded the city of Homs early on Monday, killing 15 people in a wave of attacks across several districts, activists and residents said.
This is the most violent bombardment in recent days, said one activist in Syria who was in touch with Homs residents. Another activist said forces loyal to President Bashar al-Assad were using multiple rocket launchers in the attack.
Arab satellite television stations broadcast live footage from Homs. Explosions could be heard and smoke could be seen rising from some buildings.
Activists said more than 200 people were killed on Friday night when tanks and artillery blasted the Khalidiya neighbourhood of Homs, a turbulent city that has become a centre of resistance to Assad's rule.
The latest assault, which began shortly after 2 a.m. (midnight GMT) on Monday, appeared to be more widely targeted, with explosions in Khalidiya, Baba Amro, Bayada and Bab Dreib neighbourhoods, the activists said.
Fifteen people were killed in Baba Amro and 150 wounded, one resident said by telephone. They want to drive the Free Syrian Army out, said Hussein Nader, referring to the rebel force of army deserters and gunmen who have controlled parts of the city for months.
Rockets are falling seconds apart on the same target.
Activists also said Zabadani, a town north-west of Damascus near the Lebanese border which has been largely under the control of Assad's opponents for several weeks, had come under fire on Monday.
(Reporting by Dominic Evans in Beirut and Khaled Yacoub Oweis in Amman; Editing by Louise Ireland)