A Vietnamese court on Thursday sentenced a leading independent journalist to 30 months in prison over Facebook posts that criticised the government, state media said.

Huy Duc worked for influential state-run newspapers before authoring one of Vietnam's most popular blogs and Facebook accounts, where he criticised the country's communist leaders on issues such as corruption, media control and relations with China.

The court in Hanoi convicted the 63-year-old of "abusing democratic freedoms to infringe upon the interests of the state" through posting 13 articles on Facebook, according to Vietnam News Agency.

The trial lasted just a few hours.

"These articles have a large number of interactions, comments, and shares, causing negative impacts on social order and safety," the indictment read, according to state media.

Shortly before his arrest last June, Huy Duc — which is the journalist's pen name — took aim online at Vietnam's most powerful leader To Lam, as well as his predecessor Nguyen Phu Trong.

It is unclear if the charges related to these particular posts.

Vietnam, a one-party state, has no free media and clamps down hard on any dissent. It is one of the world's top jailers of journalists, according to the Reporters Without Borders (RSF) press freedom campaign group.

The trial in Hanoi came just months after blogger Duong Van Thai -- who had almost 120,000 followers on YouTube, where he regularly recorded livestreams critical of the government — was jailed for 12 years on charges of publishing anti-state information.

In January, a prominent former lawyer was jailed for three years over Facebook posts.

'Invaluable source of information'

Huy Duc, whose real name is Truong Huy San, is a former senior army lieutenant.

He was fired from a state news outlet in 2009 for criticizing past actions by Vietnam's former communist ally, the Soviet Union.

Huy Duc spent a year at Harvard University on a Nieman Fellowship in 2012. 

During his time abroad, his account of life in Vietnam after the end of the war with the United States, "The Winning Side," was published.

RSF said previously that his articles were "an invaluable source of information enabling the Vietnamese public to access censored information by the Hanoi regime."

Rights campaigners say the government has in recent years stepped up a crackdown on civil society.

"No country can develop sustainably based on fear," Huy Duc wrote on Facebook in May, the month before he was arrested.

In December, Vietnam enacted new rules requiring Facebook and TikTok to verify user identities and hand over data to authorities.

Under "Decree 147," all tech giants operating in Vietnam must verify user accounts by phone numbers or Vietnamese identification numbers and store that information alongside their full name and date of birth.