A prominent critic of Cambodia's government was sentenced to 20 years in prison on Monday for an alleged secessionist plot, dismaying rights campaigners who decried the verdict as politically motivated.
Radio station owner Mam Sonando was also fined 10 million riel ($2,500) by a Phnom Penh court which convicted him on charges including insurrection and inciting people to take up arms against the state.
He is considered by Amnesty International to be a prisoner of conscience.
The 71-year-old, who was arrested in July, was accused of involvement in an alleged plot to establish an autonomous region in eastern Kratie province.
Rights groups have called the accusations baseless and said the government was seeking to justify its harsh crackdown on a land dispute there in May, when a teenage girl was shot dead by security forces clashing with demonstrators.
"Our court has announced a verdict that is politically motivated," the president of the Cambodian Centre for Human Rights, Ou Virak, told AFP. "There's no evidence that Mam Sonando has committed these offences."
Amnesty International researcher Rupert Abbott called the verdict "absolutely outrageous".
The European Union also expressed "serious concern" over the verdict, which it said "raises severe doubts about the impartiality and independence of the court".
Sonando, who heads the campaign group the Association of Democrats and whose station broadcasts programmes critical of the government, was jailed for peacefully exercising his right to freedom of expression, Abbott said.
"We consider Mam Sonando to be a prisoner of conscience and will be campaigning for his release," he told AFP.
Several hundred people gathered outside the courthouse to show their support for Sonando, although they were kept some distance away by the police.
As he was led into a waiting vehicle after the verdict, Sonando told reporters: "I am happy that I have helped the nation."
His wife Din Phanara told the media they would appeal the sentence.
Sonando, owner of the independent Beehive station, was arrested previously in 2003 and 2005 for his political activities and defaming Prime Minister Hun Sen's government.
The 61-year-old strongman has ruled Cambodia since 1985 and has vowed to remain in power until he is 90 years old.
Activists say land conflicts are Cambodia's most pressing human rights issue. Protests have intensified this year and campaigners say the authorities are increasingly cracking down on dissent.