Five people were also wounded by the mortar fire on the south Damascus district of Kissweh, the state SANA news agency reported.
The car bomb in Homs wounded 14 people in a district mainly inhabited members of the same Alawite community as President Bashar al-Assad, the Syrian Observatory for Human Rights said.
The central city has been hit by a series of car bombs since rebels withdrew from the city centre under a UN-brokered truce last month after enduring a withering two-year siege by the army.
The death toll from a Friday truck bombing in the central province of Hama meanwhile rose to 43, including 11 children, the Observatory said.
The bombing was claimed by the Islamic Front, Syria's largest rebel alliance.
