Thai officials plan to call for Burma's military government to release democracy activist Aung San Suu Kyi at a regional economic summit this week. Analysts remain pessimistic because Burma has never carried out early promises to free the head of the National League for Democracy.

Thai Prime Minister Thaksin Shinawatra will be making a fresh appeal for Aung San Suu Kyi's freedom during talks this week with his Burmese counterpart, General Khin Nyunt.

They will meet during a summit of leaders from South Asia, Thailand, and Burma on Thursday and Friday.

Earlier this month, U.N. Secretary-General Kofi Annan called for Thailand to do more to help free Aung San Suu Kyi. The head of the National League for Democracy has been detained for more than a year.

"There is concern over the release of Aung San Suu Kyi and the participation of the opposition NLD in the drafting of the constitution," said Sihasak Phuangketkeow, the spokesman for the Thai Foreign Ministry.

In April, Burma's government opened a national convention to draft a new constitution. But Aung San Suu Kyi's National League for Democracy refused to attend the convention unless she was freed from house arrest.

Mr. Sihasak says Bangkok continues to support efforts toward political reconciliation in Burma.

Last December, Thailand arranged multi-lateral talks, hoping that international support would help bridge the gap between the military and Burma's opposition. But Burma refused to attend a second round scheduled for April.

Many Burma political analysts remain pessimistic about the likelihood of progress, particularly because the military government has in the past promised to free Aung San Suu Kyi.

Aung Zaw, the editor of the independent Burmese newspaper The Irrawaddy, which is printed in Thailand, says Prime Minister Khin Nyunt appears to have little real influence.

"Prime Minister Khin Nyunt has little power because all the power these days seems to be controlled by Senior General Than Shwe and the army leaders, and Khin Nyunt will not be able to make a lot of promising statements or promises to the Thai leaders," he said.

Burma's military, in power since 1962, has resisted international pressure - including economic sanctions - for political reform, saying it will move toward democracy at its own pace. The NLD. won national elections in 1990, but the military never allowed it to take power, and imprisoned many of its members.