A sea battle, a bomb blast and gunfire killed at least 23 people in war-torn Sri Lanka on Saturday, government officials said, a day after the rebels denounced a government call to disarm as a joke.
Sri Lanka's military said it destroyed three Tamil Tiger gunboats on Saturday, killing at least 15 rebels.
The Tigers countered that they sank two navy boats, leaving 10 sailors dead. Both sides denied any deaths on their own side.
Fighting since last December -- which has included air strikes, mine attacks, assassinations and regular exchanges of heavy arms fire -- has killed more than 3,200 combatants and civilians, but both sides maintain they have not withdrawn from a 2002 ceasefire between the government and rebels.
The sea battle started just after dawn Saturday off the island nation's northwest coast, said Commander DKP Dassanayake, a navy spokesman.
"Our radar detected two Tiger boats approaching our shores, and we dispatched navy boats to confront them," he said.
As the navy boats drew closer, seven more boats from the rebels' naval wing, the Sea Tigers, entered the fray, he said.
"Our sailors managed to completely destroy two Tiger boats, and we estimate that 15 men would have been on board and killed," he said.
He said four Sri Lankan sailors were wounded, and that air force planes destroyed a third boat.
Dassanayake had no details about casualties in the third attack.
The Tigers' military spokesman, Rasiah Ilanthirayan, said the Sea Tigers destroyed two of the navy's fast attack craft, killing 10 sailors, after the navy attacked their training boats.
He denied military claims of heavy rebel casualties, saying only three rebels were wounded.
"Our boats are safe, and the training is continuing," Ilanthirayan said.
It is impossible to reconcile the death toll or independently verify the two sides' claims.
Also Saturday, officials said a bomb and subsequent gunfire killed four soldiers and four civilians in the country's Tamil-majority north.
The blast in the northern town of Vavuniya targeted a military truck and killed four soldiers and four students from a nearby agriculture institute, said the area's top police officer, Rohan Siriwardena.
A defence ministry official accused the Tigers of planting the bomb and firing at the troops, and said 11 civilians and three soldiers were also wounded. He spoke on condition of anonymity due to policy.
A pro-rebel website claimed that the military broke into the institute and killed the students.
Ilanthirayan denied any involvement in the blast. "We don't provoke or initiate any attacks. Even today's sea battle was only a defensive exercise," he said.
The violence came a day after Tamil Tigers denounced a government call to disarm.
President Mahinda Rajapaksa in his budget speech to Parliament on Thursday called the rebels to give up violence and disarm.
But rebel spokesman Ilanthirayan rejected the suggestion, saying, "he must be joking."
The navy regularly patrols the coast to detect weapons smuggling by the Tigers, who began fighting in 1983 for a separate homeland for Sri Lanka's minority ethnic Tamils, citing discrimination by the majority Sinhalese.
The navy has increased sea patrols after a confrontation days ago with a rebel-hijacked fishing trawler, which was smuggling in arms and ammunition.