The Sri Lankan navy has attacked a group of Tamil Tiger boats off the island's northern coast sinking five and killing 40 rebels, officials say.
The Sea Tigers are said to be based in the north of Sri Lanka
They say the clash took place off the northern port of Point Pedro, and that between 15 to 29 Sea Tiger boats were engaged in the battle.
The navy said it used gun boats and helicopter gunships in the clash.
There has been no comment from the Tamil Tigers, nor any independent confirmation of the reported sinkings.
A navy spokesman told the BBC Sinhala service that nine rebel vessels were damaged in addition to those destroyed, and that no navy personnel were hurt or injured.
"There was a cluster of boats and the navy engaged them," military spokesman Prasad Samarasinghe told AFP news agency.
"We suspect this was a diversionary move by the Tigers."
He said the Tigers usually deploy such large flotillas to distract the navy so that the rebels can carry out sea or land manoeuvres elsewhere.
The rebels have been fighting for independence since 1972.
Around 60,000 people are reported to have been killed in the conflict.