QUETTA, Oct 5: A powerful explosion rocked the Mach township late on Wednesday, police said. However, there were no reports of casualties. According to reports, unidentified saboteurs planted an explosive device close to the wall of a levies police station. The impact of the bomb was so severe that it brought down the walls of the police station and smashed the windowpanes of nearby buildings. Police said the blast was caused by a local-made bomb that was fitted with a timer. They said that a case had been registered and further investigations were in progress.