At least 45 people were feared dead in a sea battle between the Sri Lankan navy and Tamil Tiger rebels yesterday.
The violence comes amid grave fears that Sri Lanka is sliding back towards civil war.
Within hours of the attack, the Sri Lankan air force carried out air strikes
on positions close to the Tiger capital in Kilinochchi.
Fifteeen Sri Lankan sailors were missing after Tamil Tiger boats attacked a Sri Lankan naval convoy off the northern coast and sank a patrol boat, according to the Sri Lankan navy, which said it had sunk five Tiger vessels with 30 rebels on board in retaliation.
The Tigers did not confirm the casualties.
The European monitoring mission in Sri Lanka described the violence as a 'gross violation' of the 2002 ceasefire.
"This is very serious," the head of the mission, Helen Olafsdottir, said.
"It is getting worse."
The attack comes after more than 150 people have been killed in violence between government forces and the Tigers since the beginning of April.
The Liberation Tigers of Tamil Eelam (LTTE), one of the most effective guerrilla forces in the world, have their own small naval wing, the Sea Tigers.
The Sri Lankan navy said its convoy, a troop ship carrying more than 700 soldiers and its escort, was attacked by 15 Tiger vessels including suicide boats - small craft on which Tiger suicide bombers ram the much bigger Sri Lankan navy ships.
The LTTE has been fighting for two decades for an independent homeland for Sri Lanka's Tamils, who it says suffer discrimination at the hands of the Sinhalese majority.
A ceasefire has held since 2002, but this year it has begun to collapse.
- INDEPENDENT
