Sri Lanka's navy has destroyed four rebel boats and killed 14 Tamil Tigers in a clash off the island's northern coast, the government says.
Navy boats attacked a cluster of rebel vessels off the northern Jaffna peninsula, a naval spokesman said.
A rebel-affiliated website said only seven Tamil suicide fighters died and two navy boats were sunk in the battle.
The latest fighting came as Colombo stepped up military attacks against the rebels on the ground.
The Tamil Tigers could not be reached for comment on the latest incident because lines of communication to areas they hold in the north have been severed and the government bars independent reporters from the area, says the BBC correspondent in Sri Lanka, Roland Buerk.
But the pro-rebel Tamilnet website quoted them as saying they had sunk a naval attack craft and a hovercraft, and damaged another vessel.
The report added that seven members of the Black Sea Tigers, suicide fighters from the rebels' naval wing, had been killed.
The Sri Lankan military is continuing an offensive in the north of the country aimed at crushing the Tamil Tigers.
Earlier this week the Ministry of Defence said soldiers had captured the fishing port of Nachchikuda, home to the main Sea Tiger base on the north-western coast.
In recent months the Tigers have been driven from many towns and villages along the coast in the north-west and their stronghold of Killinochchi is under attack from the army in the north.
At least one senior government figure has talked of defeating the rebels militarily within two to three years.
The Tigers have been fighting for a separate homeland for a quarter of a century and about 70,000 people have been killed in the violence.