Reports say government war planes are being used for the first time over Syria’s second city Aleppo as the conflict there intensifies.
On the ground, residents say fierce fighting continues between regime forces and rebels around the old city.
Amateur video, which could not be independently verified, was said to show government tanks and helicopter gunships firing in the skies above the capital Damascus.
Meanwhile activists say Syrian forces killed up to 30 worshippers as they converged on a mosque to perform Ramadan evening prayers. The attack happened in a village northwest of the city of Hama.
The new fighting comes as US Secretary of State Hillary Clinton backs an Arab League call for President Bashar al-Assad to step down and leave Syria.
“We do believe that it is not too late for the Assad regime to commence with planning for a transition, to find a way that ends the violence by beginning the kind of serious discussions that have not occurred to date,” said Clinton.