PHNOM PENH - A Cambodian court sentenced 13 people to up to nine years in prison Friday on treason charges denounced by rights campaigners as a "concocted" smear campaign against the opposition.
The accused, including a refugee in Denmark, were convicted for plotting to overthrow the government through their Khmer National Liberation Front (KNLF) - a previously unknown group.
Only seven of the defendants - three of whom were Buddhist monks at the time of their arrest in neighbouring Thailand last year - attended the Phnom Penh Municipal Court for the verdict.
The other six were sentenced in absentia, including KNLF chairman Sam Serey who lives in Denmark.
Sam Serey was sentenced to nine years in jail, while the others were handed sentences ranging from five to eight years.
"The main goal of the KNLF is to create armed forces to oppose the government," Judge Seng Neang said.
He said members of the group - who are not well known in Cambodia - had used anti-government leaflets and planned to explode bombs at state institutions.
The defendants who appeared in court denied the accusations, screaming "No justice!" as they were taken away.
The US-based group Human Rights Watch (HRW) said on the eve of the verdict that the Cambodian authorities had no credible evidence against the group, describing the charges as "politically motivated".
"Prime Minister Hun Sen announced before last July's elections that a plot to violently overthrow the government had been broken up, seemingly intending to tar the opposition with the brush of violent extremism," said HRW Asia director Brad Adams.
"The evidence presented in court makes clear this plot was concocted and that the charges should be dropped," he added.
The opposition has denied any links to the 13 defendants.
Activists say Cambodia's judiciary is rife with political interference from the governing elite.
Hun Sen, 61, has ruled for nearly three decades and has vowed to stay in power until he is 74.
He faces mounting criticism by rights groups over a series of crackdowns on public demonstrations intended to challenge his authoritarian leadership.
On Monday the premier threatened opposition leader Sam Rainsy with legal action over a letter to King Norodom Sihamoni that appeared to rebuke the monarch for endorsing parliament despite a row over last year's disputed elections.
The warning was seen as an attempt to press Rainsy into ending a boycott of parliament.
On Thursday the opposition leader said he was close to reaching a deal with Hun Sen to end the long-running stalemate although the two sides were still at odds on when to hold the next polls.