Government spokesman Mangala Samaraweera said there was "no official" involvement with the breakaway Tiger leader V. Muralitharan, better known as Karuna, but said rogue elements of the military had been responsible.

"Obviously, there have been military personnel involved ... that we cannot deny," Samaraweera said, acknowledging for the first time that security forces were involved in backing Karuna who had been leading an underground military campaign against his former bosses.

Samaraweera, who is also the media minister, said there was no "formal" probe but believed that the defence ministry would "get to the bottom of it."

Sri Lanka's defence secretary Cyril Herath offered safe passage to Karuna when the Tigers mounted a major offensive against the renegades in the island's east in April.

Shortly after Karuna went underground after disbanding some 5,000 to 6,000 fighters under his command, the Tigers warned of "irreparable damage" to the Norwegian-led peace initiative if the Sri Lankan military or political parties moved to exploit their unprecedented rift.

Meanwhile, Norway's top peace envoy is due in Sri Lanka Monday in a fresh bid to salvage the island's faltering peace process, diplomatic sources said.

Erik Solheim, special advisor to the Norwegian foreign ministry, will spend four days in Sri Lanka and hold talks with President Chandrika Kumaratunga and Tamil Tiger leaders, the diplomats said Thursday.

Solheim was here last month to try to arrange talks between the government and the Liberation Tigers of Tamil Eelam (LTTE), but disagreements over the negotiating agenda prevented a breakthrough.

Diplomats here described Solheim's latest visit as "routine," but official sources said he would seek to jumpstart the peace talks which remain stalled since April last year.

The LTTE insists that its October 31 proposal for self-rule be taken up in talks before any final political settlement to end the three decades of ethnic bloodshed that has claimed over 60,000 lives.

Kumaratunga only accepts discussing the Tiger plan as part of a dialogue on core issues in the conflict.

Four previous attempts to end Sri Lanka's ethnic bloodshed through political negotiations failed.