One of Vietnam's best-known dissidents, Le Quoc Quan, has been sentenced to 30 months in jail for tax evasion.
Security was tight outside Hanoi People's Court where Quan appeared and where rights activists have protested against his detention.
Quan, who denied the charges, was arrested last year, accused of attempting to avoid corporate income tax at a company he founded.
His supporters say the trial was politically motivated.
Vietnam's communist rulers have opened up the economy, but suppress political opposition and ban private media. All newspapers and television channels are state-run.
The trial began and ended on Wednesday in the capital, Hanoi.
US-trained lawyer Quan, 41, has strongly maintained his innocence.
He was given a $59,000 (£36,000) fine in addition to his prison sentence for evading corporate income tax of about $30,000 (£18,000) in relation to a consultancy he had formed.
"I have long been denouncing and fighting against corruption, bureaucracy and the stagnation that is doing harm to this country... I'm the victim of political acts,'' he said after the sentence was handed down.
Correspondents say that when the verdict was announced, Quan shouted "I object" before a television feed into the court was cut off.
Hundreds of police and security officers were stationed in the streets around the court on Wednesday.
Many supporters, including the dissident's brother, gathered at a nearby church before attempting to march on the court.
Quan, a Catholic, wrote a popular blog that exposed human rights abuses and other issues not covered by the state media. He was arrested in December.
He was first detained by the Vietnamese authorities for three months in 2007, after he returned from an American government funded-fellowship in Washington.
He was beaten up in August 2012 by men he believed were state agents and, a month later, spoke publicly of threats he and his family were receiving from the authorities.
Human rights groups have accused the Vietnamese government of stepping up a crackdown against bloggers and peaceful activists. They argue that trials in Vietnam do not meet international standards of fairness.
Quan's case has been closely monitored by the US government, which is pressing Vietnam's Communist leaders to loosen their restrictions on supporters of democracy and human rights.
Correspondents say the authorities may have been seeking a compromise so that his sentence was not long enough to upset Washington but sufficient to keep him behind bars.
Three bloggers were given jail sentences of between four and 12 years in September 2012 on charges of spreading anti-government propaganda.