BEIRUT: Syrian warplanes and helicopters struck rebel enclaves in Homs on Wednesday, on the fourth day of a major offensive aimed at crushing the insurgency in the country's third-largest city, a watchdog said.
"The army used helicopters to strafe the Old City district of Homs... and warplanes and rocket fire to strike the district of Khaldiyeh," the Syrian Observatory for Human Rights said.
Although the government of President Bashar al-Assad now controls some 80 percent of Homs, several districts remain under rebel control despite a suffocating eight-month siege by the army.
Several hundred civilians are trapped in rebel-held districts of the city, which activists dub "the capital of the revolution".
"We don't know how they can get out, or where they would even go, should the army seize control of the rebel districts -- Homs is surrounded," Observatory director Rami Abdel Rahman said.
Activists said there had also been fierce early morning ground clashes between troops and rebels defending positions on the outskirts of the neighbourhoods still under their control.
In the northeast, fighter jets struck the city of Raqa, two days after rebels overran most of the strategic provincial capital in their biggest victory since the revolt against Assad's rule erupted in March 2011, the Observatory said.
Holed up in Raqa's military intelligence headquarters, their last bastion inside the city, troops fought rebels trying to seize the complex, the Britain-based watchdog added.
The new fighting came after at least 159 people were killed in violence nationwide on Tuesday, according to the Observatory's figures.
The United Nations says in all at least 70,000 people have been killed since the start of the uprising.