Syria's state news agency says a rocket has struck a prison in a suburb of the capital Damascus, killing at least four people.

SANA says Monday's attack also wounded 26 people, including a child and two women. It says most of the dead and wounded were people who were visiting relatives being held at the facility in Adra, a suburb northeast of Damascus.

Government troops retook Adra in September after months of heavy fighting with rebels.

President Bashar Assad's forces pound rebellious districts in and around Damascus on a daily basis with artillery and airstrikes, while opposition fighters frequently lob rockets and mortars into government-held areas.