Selvarasa was arrested from his residence in Kuala Lumpur recently, the source said, adding Thai Prime Minister Abhisit Vejjajiva was already informed of the information.

Earlier foreign news reports said that Selvarasa, leader of LTTE, Sri Lanka's recently defeated Tamil Tiger separatists, was captured in Thailand.

The source said that he was whisked from Kuala Lumpur back to Sri Lanka for further questioning.

Selvarasa assumed the leadership of LTTE overall following the death of its supreme leader, Velupillai Prabhakaran, in the separatist organisation's last stand against Sri Lankan security forces in mid-May.

Meanwhile, Thailand's Special Branch police chief Theeradej Rodphothong said the LTTE head was captured in Singapore, not in Thailand.

Lt Gen Theeradej noted that Thailand was mentioned in the news report becuase the LTTE head formerly had a Thai wife and he usually moved among three Southeast Asian countries - Thailand, Malaysia and Singapore.

The Thai premier earlier said that he was informed of the matter late Thursday (August 6) night and he had assigned the security agencies to seek more details.

Acting government spokesperson Panitan Wattanayakorn said an initial report said that Selvarasa had travelled in and out of Thailand but it was not identified where he was arrested.

Panitan, however, noted that Selvarasa reportedly was married to a Thai and lived in the northern part of the country.