Sri Lanka's [ Images ] military killed 13 Tamil Tiger guerrillas in three separate confrontations in the island's troubled northern areas, the defence ministry said on Friday.

Troops observed two motorcycles moving near the forward defence lines at Omanthai and opened fire on them, killing four people last evening, the ministry said.

It said another seven rebels who arrived at the scene on a tractor were also shot dead by troops.

Further north in the Jafna peninsula, troops shot dead two Tigers who tried to break into the military line at Nagarkovil, the ministry said.