KARACHI- A bomb blast killed at least four people, including a woman, and about 25 others injured in Delhi Colony today. Sindh Information Minister Sharjeel Memon cited government vehicles as a target.Memon talking to journalists at the blast site said that three government vehicles, damaged in the attack, were the target of the blast. Meanwhile, Bomb Disposal Squad said that the bomb was planted on the back seat of an old rickshaw. The explosion occurred when people were leaving the mosques after offering Friday prayers. Several other vehicles were also damaged in the attack. Five people were seriously injured. The casualties were shifted to the Jinnah Postgraduate Medical Centre for medico-legal formalities and medical treatment. Yesterday, a senior police officer was killed in a suicide bomb blast in the city.