A bomb exploded aboard a bus in Pakistan\'s Punjab province Saturday, killing at least six people and injuring 20 others, police said. The explosion occurred in the Chak Kamal area near Kharian, home to a large military base, the Press Trust of India reported. Three women and a child were among the dead and the injured were mostly civilians, authorities said. There were about 50 people on the bus. No group had claimed responsibility for the blast, which came the day after suicide bombers struck a paramilitary training center in northwestern Pakistan, killing more than 80 people and wounding 140 others. The Taliban claimed credit for that attack.