At least 25 Tamil rebels and five soldiers have been killed in fighting in two northern districts in Sri Lanka as troops tried to recapture rebel-held areas, a military spokesman said Monday.

The incidents were reported in Mannar and Vavuniya districts, more than 250 km north of the capital Sunday, he said.

In one clash in Parappakandal, Mannar, four soldiers were killed and 11 injured while 11 Liberation Tigers of Tamil Eelam (LTTE) rebels died when troops advanced to destroy a row of bunkers Sunday, the spokesman said.

In two separate incidents in the same district, 11 rebels were killed on the same day, he said. Three more rebels and one soldier were killed in clashes in Vavuniya.

Saturday rebels set off a bomb inside a passenger bus in Mount Lavinia, Colombo injuring 18 people, but casualties were minimized because an alert passenger had informed the driver about a suspicious parcel and managed to get the passengers off the bus before the explosion.

More than 80 civilians have been killed in south by rebels since January after the government withdrew from a ceasefire agreement.