The Khmer Kampuchea Krom Monks of the World said Monday they were demanding Vietnamese authorities release six men from detention, including defrocked monk Tim Sakhorn.
Group president Liv Pov told VOA Khmer they were demanding the the release of five monks in a rural province of Vietnam, Khleang, where many Khmer Krom live, and the release of Tim Sakhorn, being held in another Vietnamese jail.
The advocacy group said it would appeal to US Congress for help in their demand.
A Vietnamese Embassy spokesman denied allegations Monday that authorities there unlawfully confiscate ID cards from Khmer Krom monks, describing the accusations as political.
Vietnamese officials have said in the Tim Sakhorn was imprisoned for traveling in Vietnam with proper identification. They also said he was a Vietnamese citizen, something followers and family members in Cambodia deny.