Mortar shells hit Homs, Damascus and Hama citieskilling seven people and wounding dozens of others, Syrian security sources saidSaturday.The mortar attacks killed seven people and wounded 25 others in Homs, and wounded 13 people on the outskirts of Damascus and another one in Hama, SANAnews agency reported citing security sources.The attacks followed advances claimed recently by the opposition forces on thefronts of Ghouta district of Damascus and the northern governorate of Idlib.