Vietnamese authorities are charging 18 people with conspiracy to overthrow the government, the BBC reported Wednesday.
While few details about the supposed plot have been made public, the suspects could face the death penalty if convicted.
The charges stem from an investigation into a reactionary political organization called 'Hoi dong cong luat cong an Bia Son' in the southern Phu Yen province, Vietnam's People's Army Newspaper said after the plot was uncovered in February.
Led by a man identified as Phan Van Thu, the group allegedly planned the non-violent overthrow of the government from a den in the Hoang Long eco-tourism site, a scenic mountainous area popular with travelers.
The suspects include many of the clandestine group's officers, including the head of protection affairs, head of internal affairs and organizational chief, according to the People's Army Newspaper. There are believed to be 300 members.
This case shows that the 'peaceful evolution' strategy is being implemented by hostile forces in many ways, the newspaper said
Unnamed sources told the BBC that the 18 people were originally charged with abusing democratic freedoms, which carries a maximum seven year prison sentence, but that authorities escalated the charges.