A Nicaraguan judge sentenced four Catholic priests to 10-year prison terms on Monday, after they were charged with "treason" and "spreading false news," amid what rights groups call a growing clampdown on critics of President Daniel Ortega.

Two Catholic seminarians studying for the priesthood were also sentenced to a decade behind bars on the same charges.

The six men belong to Nicaragua's Matagalpa diocese, led by Bishop Rolando Alvarez, who was arrested alongside them last August. 

Alvarez has been placed under house arrest while he awaits trial.

A cameraman for a Catholic television channel was also sentenced on Monday to a 10-year prison term.

"We condemn these perverse actions of the regime, which violate human rights," the Nicaraguan Center for Human Rights wrote in a post on Twitter.

The group also called for the men's immediate release.

The Nicaraguan government and the country's Catholic bishops conference did not immediately respond to a request for comment.

Human rights groups have accused Ortega of targeting critical Catholic Church leaders following nationwide protests in 2018. 

Ortega accused the leaders of attempting to overthrow him when they served as mediators with protest groups during the unrest that claimed more than 300 lives.

Since then, Ortega's government has expelled Catholic nuns and missionaries, closed Catholic radio and television stations, and arrested more than a dozen priests.

Over the weekend, another Catholic priest in rural Nicaragua was also sentenced for treason and spreading false news in a separate trial.