Former Maldives president Mohamed Nasheed was sentenced to 13 years in prison on Friday after being found guilty of terrorism for ordering the arrest of a judge when he was in power in 2012.

The verdict is the latest chapter in three turbulent years in which Nasheed, the Indian Ocean archipelago's first democratically elected leader, was ousted in disputed circumstances, then narrowly defeated in a controversial election, and then, last month, cleared over the incident for which he has now been convicted.

"The prosecution's evidence proved beyond reasonable doubt that Nasheed ordered the chief judge's arrest or forceful abduction and detention on Girifushi island," Judge Abdulla Didi said in the court in the capital, Male.

The three-judge bench's verdict was unanimous, and the office of President Abdulla Yameen, who had denied that the prosecution was political, confirmed the 13-year sentence.

Nasheed's election in 2008 ended the autocratic 30-year rule of Yameen's half-brother, Maumoon Abdul Gayoom.

The announcement last month that Nasheed had been arrested on terrorism charges brought thousands onto the streets of the capital Male, leading to clashes with security forces. Countries including India and the United States have expressed concern about Nasheed's treatment and trial.

The US State Department said in a statement on Friday it was "particularly troubled by reports that the trial was conducted in a manner contrary to Maldivian law and Maldives' international obligations."