BANGKOK - THE Association of South-east Asian Nations on Tuesday expressed 'grave concern' in its first official reaction to the closed-door trial of Myanmar pro-democracy leader Aung San Suu Kyi.

The regional bloc, which rarely speaks out on the domestic political issues of its 10 members, issued a statement through current chair Thailand to urge the immediate release of the detained Nobel Peace laureate.

'Thailand, as the Asean Chair, expresses grave concern about recent developments relating to Daw Aung San Suu Kyi, given her fragile health,' the statement said.

'The Government of the Union of Myanmar, as a responsible member of Asean, has the responsibility to protect and promote human rights,' it said.

Ms Suu Kyi went on trial on Monday on charges of breaching her house arrest after John Yettaw, a US national, swam to her lakeside prison home earlier this month.

Her latest six-year period of detention was due to expire on May 27, but Yettaw's visit has apparently provided the ruling generals with an excuse to extend her detention past polls due in 2010.

The Asean statement also called for proper medical treatment for the 63-year-old Aung San Suu Kyi, who has recently been treated for dehydration and low blood pressure.

'With the eyes of the international community on Myanmar at present, the honour and the credibility of the Government of the Union of Myanmar are at stake,' it added. -- AFP