Rwanda prison authorities say a local journalist who had been sentenced to 25 years for conspiracy has escaped.

Prison spokesman Hillary Sengabo says Cassien Ntamuhanga escaped Tuesday night from Nyanza prison with two other inmates. Sengabo says they used ropes to climb over the prison wall.

Human rights groups had been outraged by the sentencing of Ntamuhanga in 2015 for conspiracy against the established government or president, complicity in a terrorist act and conspiracy to murder. The journalist at Amazing Grace radio had pleaded not guilty.

During his trial, Ntamuhanga accused police of detaining him illegally and extracting a confession under duress.

Rwanda's government has denied repeated allegations by human rights groups of restricting freedom of speech and clamping down on signs of dissent.