Residents and activists say that at least two rocket-propelled grenades have hit a building of Syria's governing Baath Party in the capital, Damascus.
If confirmed, it would be the first such attack reported inside the capital since the uprising began in March.
Meanwhile, President Bashar al-Assad said Syria would not bow down in the face of international military action over his lethal crackdown on dissent, in an interview with "The Sunday Times."
Assad told the British weekly newspaper he was "definitely" prepared to fight and die for Syria if faced with foreign intervention.
Assad said he felt sorrow for each drop of Syrian blood spilt but insisted Damascus must go after armed rebel gangs and enforce law and order.
Meanwhile, an Arab League deadline for Syria to end its repression of antigovernment unrest passed with no sign of violence abating.
The Arab League had on November 16 set the deadline for Syria to comply with a peace plan that would entail a military pullout from around restive areas, and threatened sanctions if Assad failed to end the violence.
The league, a group of Arab states, suspended Syria's membership in a surprise move last week.
Non-Arab Turkey, once an ally of Assad's, is also taking an increasingly tough attitude to Damascus.
The Syrian Observatory for Human Rights said 14 people were killed on November 19 by government security forces.
On November 18 dozens were reported killed in clashes.
compiled from agency reports