At least 60 Tamil Tiger militants and six soldiers were killed in pre-emptive operations by the security forces during the weekend in the restive northern Sri Lanka, the Defence Ministry said.While 87 rebels of the Liberation Tigers of Tamil Eelam (LTTE) were injured, 35 soldiers sustained injuries during the overnight clashes, the ministry said in a statement.In Wanni's northwestern Mannar front, troops were confronted with an attack at the LTTE defence line at Manthai, South of Adampan yesterday morning, the army said."According to the technical sources, 28 LTTE cadres were killed and 57 injured in this confrontation which continued from early morning to about 10.30 last night," the statement said.Five soldiers were killed and 26 others suffered injuries due to mortar fire and anti personal mine explosions in the incident, the military said.On the Vavuniya front, troops ran into militants defence at Periyathmapanai in Vavuniya district last afternoon, it said.Radio monitoring of LTTE transmission have revealed that 20 LTTE cadres were killed and 25 injured during the battle which took place from noon to evening.Nine soldiers sustained injuries due to anti personal mine explosions and enemy mortar fire and were admitted to Vavuniya Hospital.On the Welioya front, government troops confronted LTTE rebels at two locations last afternoon and killed two LTTE cadres and injured five others. Troops suffered no casualties in these incidents, the army said.