A roadside bomb attack blamed on Tamil Tiger rebels tore through a civilian bus in northeastern Sri Lanka on Monday, killing 12 people and injuring 17, the military said. The attack took place in the region of Welioya at about 3:40 p.m, military spokesman Brig. Udaya Nanayakkara said. «The LTTE activated a roadside bomb targeting innocent civilians,» Nanayakkara said, using the acronym for the rebel group's formal name, the Liberation Tigers of Tamil Eelam, according to a report of the Associated Press.