Despite sweeping economic reform and increasing openness to social change, including LGBT+ rights, Vietnam’s Communist Party retains tight media censorship and does not tolerate criticism.

At a one-day trial on Wednesday, the People’s Court of Ho Chi Minh City convicted 56-year-old Bùi Hiếu Võ of carrying out anti-state propaganda, according to a statement posted on the website of the party’s Ho Chi Minh City branch.

Police searched Vo’s apartment in the city last year to find 57 posts on his Facebook account that expressed views against the party and the state, it added.

The posts “encouraged people to be terrorists and could have caused public panic and hurt the economy,” it said.

The statement said Vo had collected material on Vietnam’s worst environmental disaster in April 2016, when a steel plant being developed by Taiwan’s Formosa Plastics Corp contaminated coastal waters and unleashed an outpouring of anger not seen in four decades of communist rule.

Vo used “fake” and “inaccurate” information to spread news on social media about the disaster and attacked individual leaders of the Communist Party and the state, it added.

“During the investigation Vo admitted guilt and submitted a letter asking for leniency and promising not to commit the same crime again,” it said.

Last month, Vietnam human rights activists and independent media groups wrote to Facebook’s chief executive, Mark Zuckerberg, questioning if the social media platform was helping to suppress dissent in the country.

In a separate case, police in the northern city of Thanh Hóa said they had arrested a 37-year-old man over a bid “to defame party, state, and provincial leaders,” police said in a statement on the department’s website.

Nguyễn Duy Sơn was detained on Tuesday after a police investigation found he had used his Facebook account to “humiliate and discredit” several officials, it added.

An official who answered the telephone at the Thanh Hóa police department declined to make Sơn available for comment.