The head of the Norwegian-led Sri Lanka Monitoring Mission (SLMM), Trond Furuhovde flew to the rebel-held town of Kilinochchi, 330km north of here, spokeswoman Agnes Bragadottir said.

She said Furuhovde and his deputy were already in talks with the political wing head of the Liberation Tigers of Tamil Eelam (LTTE), S. P. Thamilselvan. No details of the talks were immediately available.

The visit comes after the first major public airing of differences in the normally disciplined and unified Tigers, involving the outfit's eastern commander V. Muralitharan -- better known by his nom de guerre Karuna.

The pro-rebel Tamilnet.com website denied there was a "major split" in the LTTE, led by elusive supremo Velupillai Prabhakaran, 49, who is based in the north of the island.

"We will be functioning directly under the command of our leader," Tamilnet quoted a spokesman of Karuna as saying. He said: "There was no split in the LTTE."

However diplomatic sources said Karuna, who is also a member of the Tigers' peace negotiating team, had informed Norway through his aide that he should be treated as a separate entity, signalling his dissent.

Karuna had also asked the government military to help him bring back forces loyal to him from the north of the country, a military official said.

Local rebel sources said Karuna had been unhappy about two killings in his area apparently carried at the orders of another less senior leader based in the north.

Sri Lanka's government of Prime Minister Ranil Wickremesinghe as well as the party of President Chandrika Kumaratunga reacted cautiously.

"There is a problem, but we have no reason to believe that the continuation of the ceasefire agreement is in doubt," government spokesman G. L. Peiris told reporters here.

Kumaratunga's party spokesman Mangala Samaraweera too declined comment saying they were still studying reports and did not want to comment on internal matters of the rebel movement.