Army spokesmen said guerrillas from the separatist Liberation Tigers of Tamil Eelam (LTTE) were ambushed by troops near the northern town of Oddusuddan, which was retaken by the army earlier this month.

The report has not been independently confirmed.

The army said it ambushed a tractor pulling three trailers packed with up to 50 rebel fighters on the road leading to one of the Tiger's main naval bases on the north-east coast.

The soldiers used machine guns, rocket-propelled grenades and mines.

Drive continues

BBC Sri Lanka Correspondent Susannah Price says government troops appear to be continuing their offensive towards the north-eastern Tiger stronghold of Mullaitivu.

Tamil Tiger leader, Velupillai Prabhakaran: No comment yet on ambush

Army commander Lieutenant-General Srilal Weerasuriya, who took office last week, said this would remain the military objective.

He said the Tigers' fighting capability had diminished. But correspondents say Sri Lankan troops are still likely to encounter strong resistance if they continue to push along the road to Mullaitivu.

In a separate clash in the eastern district of Batticaloa, rebels threw grenades at an army convoy, killing a soldier and wounding eight others, the army said.

There have been sporadic clashes between the two sides in the past two weeks but no major confrontations since September, when more than 900 died on both sides in several big battles.

The guerrillas are fighting for a homeland in the north-east for the country's minority ethnic Tamils. They say the majority Sinhalese - who control the government and military - discriminate against them.