Seventeen Tamil Tiger rebels have been killed in fighting in the northern districts of Vavuniya and Mannar, the Sri Lankan military has said.
Clashes are worsening between the two sides
The military said one soldier was killed in the fighting in Vavuniya. The Tigers have not commented on the claim.
Earlier this week, dozens of soldiers and rebels were reported killed or wounded in fighting in the north.
Fighting between troops and the rebels, who want autonomy in the north and east, has worsened in recent months.
The leader of the Tigers' political wing, SP Thamilselvan, was killed on 2 November in an air strike.
A Norwegian-brokered ceasefire in 2002 broke down after several years, resulting in renewed fighting that has killed more than 5,000 people.
At least 70,000 people have died since the war began in 1983.