Malaysia has told Thailand to provide proof that its most wanted man, an alleged Islamic militant in detention here, is a Thai national and again pressed Bangkok to use diplomatic channels for negotiations.

The comments by Foreign Minister Syed Hamid Albar were the latest in a war of words between the two countries about the alleged mastermind of a Muslim separatist uprising in southern Thailand which has left at least 570 people dead in the past year.

Thai Foreign Minister Surakiart Sathirathai said on Tuesday that Chae Kumae Kuteh, also known as Doramae Kuteh, held Thai nationality and that Malaysia and Thailand had had an extradition treaty since 1911.

Syed Hamid said Malaysia had "solid proof" that the man was a Malaysian citizen.

"We do not have documents to show that he is a citizen of another country. If another country were to say it, it's up to that country to prove it," he was quoted as saying by Bernama news agency.

M'sian not happy

Syed Hamid, repeating a complaint which led to a sharp exchange last week, said Thailand should go through the proper diplomatic channels if it wanted the suspect extradited.

Malaysia had not received a formal application for his extradition, he said, adding that resorting to the media could be misconstrued and create confusion.

Malaysia and Thailand had very close relations and adequate mechanisms to resolve any issue and must abide by the legal process, he said.

The Thai foreign minister told reporters that Thailand would give the Malaysian embassy evidence that the suspect was a Thai and that the two countries had signed a treaty that would allow for his extradition.

"We have firm evidence that he is a Thai national," he said.

"Thailand's position is that we have had an extradition treaty since 1911, and that the agreement has since been reaffirmed," most recently last year, he said.

No extradition treaty?

Malaysia's Prime Minister Abdullah Ahmad Badawi said last Thursday: "We have no extradition (treaty) with Thailand but if Thai authorities want to seek some help from us in whatever way, (if) they want to know the activities of this man, we will be able to cooperate."

Mainly Muslim Malaysia has pledged to cooperate with mainly Buddhist Thailand in its attempts to quell the separatist rebellion.

But it has frequently been irritated by Thailand's remarks to the media over alleged cross-border movements of Muslim militants, many of whom share a kinship with Malays in Malaysia's northern states.