NEW DELHI (Reuters) - Four boys were killed on Tuesday by a bomb blast in the southern Indian city of Coimbatore, United News of India said. Police in the city, where 17 bomb blasts and a confrontation between security forces and suspected militants last weekend killed 54 people and injured more than 200, could not immediately confirm the report. Police confirmed a previous report that three children had been injured by a bomb. "At about 11 a.m. (0530 GMT) this morning, three children who were playing on the side of the street in Majid colony were seriously injured when a bomb exploded nearby," a senior officer told Reuters, adding that they had been admitted to the local government hospital. The weekend bombs, most of which were planted in cars, went off around the time that Hindu nationalist party leader Lal Krishna Advani was scheduled to address an election rally. One of the bombs went off close to the venue of the meeting. No group has claimed responsibility for the blasts, which triggered rioting, arson and looting. The authorities have banned two Islamic groups and arrested eight militants in Coimbatore since Saturday.