Rwanda's High Court has sentenced an opposition leader to four years in prison and fined three others opposition figures in a trial that an international human rights body said was politically motivated.

Bernard Ntaganda, the founder of the PS-Imberakuri party, was sentenced Friday for endangering national security, attempting to organize unauthorized protests and inciting ethnic divisions. Three members of another opposition party, FDU-Inkingi, were fined.

Human Rights Watch said the sentences are a blow to freedom of expression and democracy, and that Ntaganda has criticized the government but has not called for violence.

"These are blatantly political trials," said Daniel Bekele, Africa director of Human Rights Watch, adding that Ntaganda and others "are paying a heavy price for daring to express their opinions."

The sentences come a week after two female journalists, Agnes Nkusi Uwimana and Saidaiti Mukakibibi, were sentenced to 17 and seven years respectively for publicly criticizing the government in published articles.

But Rwanda's National Public Prosecuting Authority issued a statement welcoming Friday's sentences.

"There is no place for hate speech and divisionism in Rwanda. Our laws are there to protect Rwandans from those who want to reverse the economic and social progress as well as the reconciliation that has been made in the last 17 years," said Martin Ngoga, Rwanda's Prosecutor General.

The Rwandan government contends its strict laws are necessary to prevent a repeat of the 1994 genocide, in which hundreds of thousands of Tutsis and moderate Hutus were killed.

Ntaganda had founded the opposition PS-Imberakuri party but was ousted from his leadership position in March. He was arrested in June, six weeks before the presidential election that his party and several others were unable to participate in. Incumbent Rwandan President Paul Kagame won with 93 percent of the vote.