At least four persons were killed as Sri Lankan troops launched ground, air and sea attacks against Tamil Tiger rebels in the island's northeast, the military said on Monday.

The Sri Lankan Navy troops patrolling the shores off the north-eastern Trincomalee district sank a rebel craft after a three-hour sea battle on Monday that left three government sailors wounded.

Navy sources said they believed at least six rebels may have been aboard the boat that was sunk.

The fighting started after Naval personnel intercepted a group of Sea Tiger boats moving toward the Pulmodai area on the northeast coast.

The Navy said several Tiger boats were damaged in the skirmish while the pro-rebel Tamilnet.com website claimed that three Sri Lankan gunboats also were damaged.

Three Tamil Tiger rebels and a soldier were killed in a gunfight last night at Pulmodai, the Defence Ministry said.

Sri Lankan war planes early today bombed suspected rebel positions at Nedunkerni area to neutralise a guerrilla artillery position. There were no immediate reports of rebel casualties nor was there any reaction from the Tigers.

The Tigers are fighting for an independent homeland for minority Tamils. The ethnic conflict has claimed more than 60,000 lives since 1972.

A Norwegian-brokered ceasefire agreement in 2002 scaled down the violence, but fighting intensified again in late 2005. More than 5,000 people were killed in the new wave of violence in the island nation.