At least 60 people have been arrested at an anti-government protest in Nigeria's capital Abuja, according to protest organisers Revolution Now.
The police have not said what their alleged offences are.
The nationwide protests marked a year since the first demonstrations by the movement.
The former presidential candidate and founder of the news site Sahara Reporters Omoyele Sowore started the Revolution Now movement last year.
He called for a revolution saying last year's election, in which President Muhammadu Buhari won a second term, was not credible.
He has since been charged with treason, money laundering and "cyberstalking" for allegedly sharing false and insulting information about President Buhari.
He denies all the charges.
He was held in detention for 130 days before eventually being released on bail and is currently awaiting trial.