The Syrian military launched an offensive to regain control of suburbs on the eastern edge of Damascus Sunday, storming neighborhoods and clashing with groups of army defectors in fierce fighting that sent residents fleeing and killed at least three civilians, activists said. Six soldiers were also killed when a roadside bomb detonated near the bus they were traveling in several miles south of the capital. Activists said government forces dispatched dozens of tanks and armored vehicles to reinforce troops in a belt of suburbs and villages on the eastern outskirts of Damascus where armed defectors have grown increasingly bold, staking out positions and setting up checkpoints in recent days.