At least 29 Syrian rebels were killed Sunday when a car exploded in the besieged central city of Homs.
A British-based monitoring group, the Syrian Observatory for Human Rights, said the death toll from the blast could increase, with "dozens of missing persons in the area."
There was no immediate explanation for the explosion.
Earlier, in a separate incident, the state news agency SANA said a mortar fired by rebel fighters struck the Damascus Opera House, killing two.
A British-based monitoring group, the Syrian Observatory for Human Rights, said the death toll from the blast could increase, with "dozens of missing persons in the area."
There was no immediate explanation for the explosion.
Earlier, in a separate incident, the state news agency SANA said a mortar fired by rebel fighters struck the Damascus Opera House, killing two.