Armed groups fired a hand-made rocket at a square in Syria\'s capital Damascus on Saturday, hitting a residential bloc and injuring two young girls, local media said. The rocket hit a building at the George Khouri Square in al- Qassa district, which is dominated by Christians. Three floors of the building have been damaged and two young girls injured, one of whom is in grave condition, the reports said. The rocket firing coincided with four blasts that rocked Syria on Saturday. Three blasts caused by car bombs have rocked the southern province of Daraa earlier in the day, killing at least seven people. Another explosive-loaded car went off in the Damascus\' district of Tadamun and injured nine. Explosions have become increasingly common and almost daily occurrences particularly in Damascus, in what appeared to be the rebels\' latest tactic to erode the Syrian administration grip on the capital.