- The death toll is expected to rise in Douma, opposition activists say
- Thousands of children have died in Syria's 4-year-old civil war
Government forces shelled and launched rockets on the city in the countryside outside Damascus, the London-based Syrian Observatory for Human Rights said.
The group said the death toll is expected to rise, as many of those injured are in critical condition and there are people missing -- possibly buried under rubble.
For its part, the state-run Syrian Arab News Agency
reported Sunday that regime forces destroyed ammunition, a rocket launcher and a cannon in the Damascus countryside.
Sunday's violence marks another bloody day in Syria's 4-year-old civil war. What started as a political protest in 2011 was met by a violent government crackdown, which then led to an armed uprising and a civil war.
Last year, the United Nations estimated about 200,000 people -- including thousands of children -- have been killed in the civil war, though the exact death toll is likely to be much higher.
Syrian rebels have been trying to oust President Bashar al-Assad, whose family has ruled Syria for more than 40 years. Despite widespread reports of government bombings and even chemical warfare in civilian areas
, the regime has maintained that it is targeting terrorists.