Zimbabwe police on Thursday used batons to break up a courthouse protest by opposition supporters, angered by the continued detention of dozens of activists arrested in mid-June, after they allegedly gathered without official police clearance.

Dozens of opposition Citizens Coalition for Change supporters had gathered at the magistrates' court in the capital, Harare, and broke into protest songs and chants demanding freedom for 78 activists who had been denied bail by a magistrate.

Skirmishes ensued as police who had maintained a strong presence shoved a lawyer who was addressing journalists outside the courthouse, before clashing with opposition supporters.

The detained activists, including Jameson Timba, interim leader of a faction of the splintered opposition party, have been in detention since June 16 when they were arrested at Timba’s residence in Harare. Their lawyers say they were at the house for a barbecue to commemorate the Day of the African Child, a calendar event of the African Union.

They are facing charges of disorderly conduct and participating in a gathering with the intent to promote violence, breaches of peace or bigotry. They face a fine or up to five years in prison if convicted.

Last week, Amnesty International described the arrests and detention as “part of a disturbing pattern of repression against people exercising their rights to freedom of peaceful assembly and expression.” The rights group called for an investigation into allegations that some of the activists were tortured while in police detention.

Amnesty and other global and local rights groups say the clampdown highlights continued repression, including pretrial detention, of the opposition and other government critics such as university students and labor unionists.

President Emmerson Mnangagwa, who promised democratic reforms after taking over from the late repressive longtime ruler Robert Mugabe in a coup in 2017, denies the allegations, but has also repeatedly warned the opposition against inciting violence.