Syrian warplanes kept up air raids on rebel strongholds in and around the capital Damascus on Wednesday, according to activists.
Amateur video purportedly showed air bombardments on residential areas of the city including eastern Ghouta and Zamalka.
State media reported that a bomb killed at least six people near a Shi-ite shrine in another suburb.
A four-day ceasefire at the weekend was left in tatters after violence killed more than 500 people.
Also on Wednesday, the new Syria peace envoy Lakhdar Brahimi held talks with China’s foreign minster calling for Beijing to play an “active” role in efforts to end the civil war.
Later, a Chinese statement called for greater international support of Brahimi’s mediation efforts.
China and Russia have vetoed three UN resolutions condemning the Assad regime for the violence.
Meanwhile, Syrian rebels revealed how they make cheap homemade bombs after extracting TNT from unexploded regime artillery rounds.
They claimed to make 50 to 60 hand grenades for each mission.
Video footage was filmed over the weekend at a rebel camp close to the border with Turkey.