Thailand's foreign minister has expressed concern over Burma's refusal to say when it will free democracy activist Aung San Suu Kyi.  Kanthati Supamongkhon's comments followed a sudden and secretive half-day visit to Burma he made with the Thai prime minister.

Foreign Minister Kantathi Supamongkhon said Thursday that Thai officials relayed international concern over the continuing house arrest of Burmese democracy activist Aung San Suu Kyi.

"A message that we try to convey to Myanmar is to keep them informed of the concerns of the international community - concern of ASEAN - concern of Thailand and how it would be a positive thing for Myanmar to progress in democracy," he said.

On Wednesday, Kantathi joined Prime Minister Thaksin Shinawatra, army chief Sonthi Boonyaratglin and other top officials on a brief visit to neighboring Burma.

Kantathi says the trip was primarily aimed at managing relations with Burma and that the officials did not conduct specific negotiations over trade and business deals.

The foreign minister's comments were among the few details to emerge from Wednesday's half-day meeting in Burma's newly designated capital, Pyinmana.

Thaksin Shinawatra, left, with Myanmar's Chairman of State Peace and Development Council Senior Gen. Than Shwe, right, during meeting in Myanmar, Aug. 2, 2006

Prime Minister Thaksin earlier had said he did not know if he and Burma's leader Than Shwe discussed the detained Nobel laureate.

Mr. Thaksin was also vague when he described the visit's agenda.

"[It] covered every issue: social, economic and political," he said.

Political observers in Bangkok have expressed concern about the few details given about the official visit. Panitan Wattanayagorn is a political scientist from Chulalongkorn University.

"This is quite unusual practice and we're still waiting for a clearer explanation as to what extent this meeting is conducted in a very urgent manner," he said.

Mr. Thaksin's political opponents charge the lack of detail is typical for a prime minister who shows little interest in government transparency.

The visit to Burma was the prime minister's first since December 2004, and it was the first visit by a foreign head of government to Burma's new capital.

Before the trip, Mr. Thaksin said the Association of Southeast Asian Nations asked him to relay ASEAN's concern about the lack of democratic reforms in Burma.

Last week, the 10-nation group called on Burmese officials to make "tangible progress" on moving toward democracy and to free political prisoners.

On Tuesday, Washington singled out Burmese officials for criticism when President Bush renewed the Burmese Freedom and Democracy Act. The move extends import restrictions against the government for up to three years.