Two civilians and a Catholic priest were among 21 people killed in northern and north-western Sri Lanka in bombings and clashes between Tamil rebels and government forces, military officials said Thursday, according to dpa. The two civilians were killed Thursday when a mine placed on a bicycle was triggered as a police vehicle was passing by in the Chunnakam area, 370 kilometres north of Colombo, military officials said. At least 17 civilians and two policemen were injured in the blast. A Catholic priest carrying food and milk to people displaced by fighting between the government and separatist Tamil rebels was killed Wednesday in a similar claymore mine explosion in Mannar, 320 kilometres north of Colombo. The incident took place in a rebel-controlled area, and rebels said Army units that infiltrated into their territory carried out the killing, a claim denied by the Army. Four rebels were killed Wednesday in Muhamali, 350 kilometres north of Colombo, as they attempted to breach forward defence lines into a military-controlled area, the military said. In two separate battles in Vavuniya, 240 kilometres north of Colombo, 13 rebels and a soldier were killed Wednesday in clashes that began when rebels made other attempts to cross into government-controlled areas, a military spokesman said. Sporadic fighting in northern Sri Lanka since Sunday has left more than 75 rebels dead, the Army said.