Updated

A human rights group is calling on Thailand's military junta to release an opposition activist who appeared on an army television channel saying her treatment in detention was "too good for words to say."

Kritsuda Khunasen, an activist with the grassroots Red Shirt movement, has been missing since security forces detained her May 28 in Chonburi province, east of Bangkok.

In an effort to prove she was alive and being treated well, the army's Channel 5 TV station aired several minutes of footage late Monday showing Kritsuda sitting at a table talking about her situation.

The group Thai Lawyers for Human Rights urged authorities to release Kritsuda immediately and said her whereabouts remain unknown.