Vietnamese authorities arrested blogger and independent journalist Pham Chi Dung, a prominent government critic and VOA contributor, in Ho Chi Minh City Thursday.
In a statement posted online, Vietnam's Ministry of Public Security accused Dung of "dangerous" anti-state actions, including "fabricating, storing, and disseminating information, as well as other materials opposing the Vietnamese government."
State media said Dung carried out "anti-regime activities such as producing anti-state articles, [and] cooperating with foreign media."
Dung, 53, president of the outlawed Independent Journalist Association of Vietnam (IJAVN), could face a jail sentence of five to 20 years if found guilty, local media said.
Dung, who writes regularly on VOA's Vietnamese Blog, faced similar allegations in 2012.
IJAVN vice president Nguyen Tuong Thuy told VOA that Dung's arrest was "a dangerous move to silence dissenting voices and repress freedom of speech in Vietnam."
IJAVN's website has been blocked since Dung's arrest. Thuy said he fears "the arrest will have a big impact on the group's activities and its members," as authorities continue to investigate the group.
Dung established IJAVN as a "civil society organization," July 4, 2014, and has said that America's Independence Day inspired him to create a platform to advocate for freedom of the press, freedom of expression and democracy.
"The arrest of Pham Chi Dung is the continuation of an intensified crackdown against political activists and bloggers in Vietnam," freelancer Duong Van Thai, a Vietnamese political asylum seeker in Thailand and a former state-run media reporter in Vietnam, told VOA. "The arrest showed Hanoi's desire to exercise greater control over the freedom of speech."
Nguyen Tuong Thuy noted that Dung's criticism of the government had intensified of late, likely triggering his arrest.
"He has written more aggressively in a stronger style, but Pham Chi Dung is still the same!" Thuy said
Dung resigned from the Communist Party in 2013, ending 20 years of membership. In the years since, Reporters Without Borders has lauded him as an "information hero." In addition to VOA, he has contributed to NBC News and Nikkei Asian Review.
The Vietnamese government continues to ban independent or privately-owned media outlets. It exerts strict control over radio and TV stations and printed publications, and routinely block access to politically sensitive websites.