The deaths -- which now total 118 since Monday -- have made a mockery of a truce in place since February 2002, although both the government and the Tigers have said they are still committed to it.

Top Norwegian peacebroker Erik Solheim urged Sri Lanka and the rebel Liberation Tigers of Tamil Eelam (LTTE) to end the fighting, which began on Wednesday last week after the military moved to open an irrigation canal blocked by the Tigers.

"We very strongly appeal to stop the offensive operations immediately," Solheim, who is also Norway's International Development minister, said in Oslo.

Sri Lanka's President Mahinda Rajapakse telephoned Indian Prime Minister Manmohan Singh on Tuesday night to brief him on the fighting in the Trincomalee district where India has commercial interests, a spokesman for the president said, without giving details of the discussions.

The Tigers slammed the government for launching a military offensive on what they called the pretext of a dispute over water.

"There was an urgent humanitarian need to neutralise the Sri Lankan militarys attacks on civilian targets," the LTTE's military spokesman I. Ilanthirayan said in remarks published on the pro-rebel Tamilnet.com website.

He said the LTTE had targeted the militarys artillery bases as well as the supply lines to troops massed in the Maavilaru area of Trincomalee district, where the canal sluice gates are located within a rebel-held area.

"Wednesdays operations against several Sri Lanka army bases along the A-15 main supply route from Muttur to Maavilaru were also essentially defensive actions," Ilanthirayan said.

Tuesday's shelling of the Trincomalee naval port was also part of that strategy, he said, denying military claims that the rebels targeted a navy troop carrier with over 800 unarmed soldiers aboard.

"It was not a specific target, but entered the LTTEs theatre of defensive action," he said adding that two Black Tiger suicide bombers and seven others were killed outside Trincomalee harbour Tuesday.

The military said it destroyed at least four rebel boats outside the harbour, killing an unspecified number of rebels. The navy lost four sailors killed and 30 wounded in Tuesday's attacks.

The pre-dawn Tiger artillery barrages Wednesday targeted three army camps and the town of Muttur, a mainly Muslim fishing town which is supplied by water from the Maavilaru irrigation system 10 kilometres (six miles) away.