A prodemocracy Myanmar activist in the Japanese arm of Aung San Suu Kyi's National League for Democracy has been detained since March and his supporters are calling for his release.

Aung Tin Oo, 29, an executive member of the Japanese unit of the NLD-Liberated Area, the party's overseas organization, has been detained by the Nagoya Immigration Bureau on suspicion of illegal disembarkation, the supporters said.

Aung was supposed to head an NLD-LA office in Nagoya, which opened last weekend in his absence. His supporters submitted a petition with more than 1,000 signatures for his provisional release to the immigration bureau last month.

Aung, a sailor, landed in Japan without permission after his ship arrived in Nagoya in May 2001, and has since stayed illegally in Japan doing part-time jobs, the supporters said.

After engaging in activities to promote democracy in Myanmar, Aung was named as the first head of the Nagoya office with seven members.

However, he was detained by authorities at a 24-hour supermarket in Nagoya early on the morning of March 15, they said.

After he was detained, Aung submitted a prepared application for refugee status to the Justice Ministry.

The ministry rejected his request, saying he did not belong to an antigovernment organization and his activities in Japan were not recognized as dangerous by the Myanmar government.

"We cannot comment on individual cases, " an immigration official said.