Colombo  - Government troops and Tamil rebels clashed in northern Sri Lanka leaving behind at least 13 rebels and two soldiers dead and more than 15 injured, a military spokesman said Tuesday.

Fighting was reported from the Mannar, Vavuniya, Jaffna and Welioya areas, more than 250 kilometres north of the capital as government troops continued their advance into rebel held areas in the north.

Seven of the rebels were killed when troops exchanged mortar and small arms' fire with the rebels in Mannar on Monday. Four soldiers were also injured in the same area, he said.

Two soldiers and five rebels were killed in combat in Welioya Monday, the military spokesman said. At least 11 rebels were also injured.

Fresh clashes also broke out in the Nagar Kvoil and Muhamale area of the Jaffna peninsula killing a rebel on Monday.

Tamil rebels set off a powerful claymore mine in north central Sri Lanka targeting a group of paramilitary guards on Tuesday morning, but only two guards were injured in the incident when the mine detonated prematurely, military officials in the area said.

The blast occurred in Kebithigollewa, 220 kilometres north of the capital where the government has increased security for the villagers to prevent them coming under rebel attacks.

Fighting in the northern part of the country has intensified with the military stepping up operations and the rebels putting up resistance during the past three months.

The military claims to have killed more than 2,500 rebels during the past three months and lost more than 300 soldiers. (dpa)