A number of people were killed and injured in attacks by mortar shells in many areas in Syria on Sunday, official news agency (SANA) reported. One citizen was killed when a mortar shell crushed into Abbasid Square while six nationals were injured by mortar shells on neighborhoods of Bab Sharqi, Qassa\' and Qadam, SANA quoted an official source as saying. Four shells hit Sufaniya Park in Bab Sharqi wounding three citizens and causing damage to seven vehicles, added the source. A person was killed and 20 injured in mortar shells\' attack on Wafideen Camp outside Damascus, he said. Opposition gunmen warned people of Damascus to leave their houses located near government security departments because they would attack them. Other attacks by motar shells destroyed properties and cars but did not result in casualties.