COLOMBO: Sri Lanka announced on Monday that it was halting the use of heavy weapons and air strikes to spare civilian lives in its battle against the Tamil Tigers, but asserted it was not calling a truce.

The rebels immediately accused the government of merely trying to deflect international pressure, and said fierce fighting continued to rage. The Tigers also said they would "never surrender" despite being out-gunned and surrounded.

The statement from President Mahinda Rajapakse said "combat operations have reached their conclusion," and that the "use of heavy calibre guns, combat aircraft and aerial weapons which could cause civilian casualties" would stop.

A government official said the statement only heralded a change in tactics and that fighting was continuing. Sri Lanka's military has also been saying for months that they were not firing heavy weapons into rebel-held territory.

"This was no reaction to any 'international pressure,' but solely timed with the success of the ongoing world's largest hostage rescue operation," the defence ministry also said.

The Sri Lankan government says its forces have cornered the Tamil Tigers in a small strip of coastal territory in the northeast, but it has been under pressure to spare the lives of tens of thousands of trapped civilians.

A United Nations document circulated among diplomats in Colombo last week said as many as 6,500 civilians may have been killed and another 14,000 wounded in the government's offensive this year.

The rebels meanwhile accused government troops of continuing to pound their territory.

"They are only paying lip service to pacify the international pressure," rebel spokesman S. Puleethevan told AFP by telephone. They have carried out two aerial attacks this afternoon."

He also vowed the Liberation Tigers of Tamil Eelam (LTTE), who are fighting for an independent Tamil homeland, would not give up -- even with the odds stacked against them.

"We made our position very clear... We will never surrender till our legitimate demands are met," he said.

The latest government move came as the UN's top humanitarian official, John Holmes, was visiting the island with a plea to both the administration and the Tamil Tigers to spare civilians trapped in the war zone.

Some 110,000 civilians escaped from the rebel-held sliver of territory on the island's northeastern coast last week following a major military push.

The United Nations estimates that some 50,000 non-combatants are still trapped in the conflict area, while the government maintains that the number is fewer than 20,000.

The pro-rebel website Tamilnet, however, said 160,000 civilians were still sheltering in the area and continued to be subjected to heavy shelling.

Holmes is also due to meet Sri Lankan President Mahinda Rajapakse on Monday evening, before wrapping up a three-day visit that is to be followed by a trip to Colombo by the foreign ministers of Britain, France and Sweden on Wednesday.

Holmes had on Sunday appealed to both sides to stop the violence, saying that recent fighting had taken "a terrible toll" on civilians.

The rebels offered a unilateral ceasefire on Sunday, although this was dismissed by Sri Lankan Defence Secretary Gotabhaya Rajapakse -- the powerful brother of the president -- as "a joke."

"What is the need for a ceasefire when they are running away? They should first lay down arms, surrender and let the people go," Rajapakse said.