At least 70 people have been killed at protests in Guinea in the last four years, according to a report by human rights organisation Amnesty International.
Thousands have hit the streets in multiple protests over a suspected effort by President Alpha Condé to seek a third term.
The rights group says people who protest peacefully are being jailed.
It says five of the leaders of the protest group National Front for the Defense of the Constitution were sentenced to up to one year in prison after they were arrested on 12 October this year.
Among those killed, Amnesty noted the killing of a student, Amadou Boukariou Baldé, who it says was beaten to death by paramilitary police officers at a protest at the University of Labé in central Guinea in May.
Mr Condé has been president since 2010.