Police in communist Vietnam on Tuesday arrested a pro-democracy activist, his father and state-linked media said, a day after his dismissal from the military.
Nguyen Tien Trung, 25, had links with human rights lawyer Le Cong Dinh, the VNExpress news website reported, quoting security sources.
The lawyer's high-profile arrest last month sparked concerns from European countries and the United States, as well as human rights watchdogs and press freedom groups around the world.
Trung was arrested at his family's home in southern Ho Chi Minh City, his father told AFP.
"The police had an arrest warrant accusing him of propaganda against the state," Nguyen Tu Tu said.
VNExpress said Trung is accused of opposition to the state and was arrested following his expulsion from the military, where he was performing national service.
VNExpress said Trung, while he studied in France, put in place the "Movement of Democratic Youth" as part of efforts demanding political change in Vietnam.
Authorities say he spread his message through the Internet and after returning to Vietnam discussed with others making the Democratic Party of Vietnam "official", VNExpress said.
It said Trung sought the lawyer Dinh's participation in the party.
Its founder Hoang Minh Chinh, a former Communist Party intellectual who later became its critic and was imprisoned, reactivated the banned Democratic Party of Vietnam in 2006. He died in 2008.
Trung's detention came a day after the arrest of another pro-democracy activist, Tran Anh Kim, VNExpress said.
Kim, 60, is being investigated for propaganda against the state and was also involved with the Democratic Party, VNExpress said, citing security forces.
It said he is also a regional executive of the outlawed Bloc 8406 group that has called for multi-party democracy.
The arrests are the latest in a series of dissident detentions since early 2007.