By Anna Horsborough Porter BBC correspondent in Sri Lanka

The Norwegian-led mission in Sri Lanka monitoring the country's ceasefire has accused separatist Tamil Tiger rebels of holding two members of the team against their will on a rebel vessel.

I hope we will be able to find ways to keep walking towards peace

General Furuhovde, SLMM commander

Major General Tronde Furuhovde, the Norwegian head of the Sri Lanka Monitoring Mission has called the incident a serious violation of the ceasefire agreement, and a major blow to the trust of the SLMM in the Tamil Tigers.

A statement issued by the SLMM describes how the incident occurred.

Two trawlers belonging to the Liberation Tigers of Tamil Eelam (LTTE) entered Sri Lankan territorial waters in Palk Bay, south of the Jaffna peninsula, on Saturday evening.

They were intercepted by the Sri Lankan navy, and one trawler fled the scene.

Rebel rejection

The Sri Lankan Navy sought the advice and assistance of the naval SLMM monitors in Jaffna, who having obtained the full agreement of the Tamil Tiger political leadership in Kilinochi, went aboard the vessel.

Rebel boats broke the ceasefire agreement

According to the SLMM statement, the two monitors found communication equipment on board which was controlled by four rebel soldiers.

The SLMM then suggested that the vessel be vacated and taken into the custody of the Sri Lankan navy as it was in violation of the terms of the peace agreement.

This was rejected by the Tamil Tiger leadership.

The four rebel soldiers refused to disembark, and started to move the vessel heading towards the Tamil Tiger-controlled coastal area.

Peace doubts

The statement says that at this time the two SLMM naval monitors were held against their will by the Tiger cadres, and physically hindered from leaving the trawler.

The SLMM's trust in the rebels has been shaken

The vessel was then brought ashore in the early hours of Sunday morning and the monitors were released.

General Furuhovde ended the statement with strong criticism of the Tamil Tigers.

He said such mistreatment of members of his mission was extremely counterproductive.

He added that after this irresponsible behaviour the Tamil Tigers will have to do a lot to rebuild people's confidence in their organisation.

He said: "I hope we will be able to find ways to keep walking towards peace, and I hope that the LTTE is still ready to do so."