Sri Lankan military helicopters attacked Tamil Tiger sea fighters in the country's north, while ground fighting across the region killed 20 insurgents, AP quoted the military as saying today. The air force targeted rebel sailors in Pooneryn in Jaffna district Thursday night, a military statement said, without providing further details. Infantry battles across the northern front lines Thursday killed 20 insurgents, the military said. Eleven were killed in the rebel stronghold of Kilinochchi, six in Welioya and three in Vavuniya, it said.