Sri Lankan Navy, assisted by helicopter gunships, on Saturday destroyed three Liberation Tigers of Tamil Eelam boats, killing at least 15 of its cadres, while rebels said they sank two naval vessels in a fierce sea battle off the island's north-western coast.

Also, three soldiers lost their lives when rebels set off a landmine blast while another three students were killed in retaliatory firing by the army in Vavuniya district of northern Sri Lanka [Images] on Saturday.

The navy said it confronted a group of Tamil Tiger boats off the island's north-western coast and sank three of them after receiving support from helicopter gunships and F-7 Chinese jets.

At least 15 rebels were killed in the assault, but the rebels said they suffered no losses. The navy said four sailors were also wounded.

However, the LTTE said they sank two naval inshore patrol craft and killed at least 10 sailors.

Rebels set off a powerful landmine in the northern district of Vavuniya on Saturday, killing at least three soldiers and wounding three more, police said.

They said three students were also killed and another 12 wounded following the blast near a farm and believed that they may have been hit in retaliatory firing by the troops.

The Sri Lankan military accused the Tigers of taking the cover of students to attack the army.