Zimbabwe warned against opposition protests before a regional summit in the country later this month, when President Emmerson Mnangagwa will assume the chairmanship of a southern African economic bloc.

The country will host heads of state for a meeting of the Southern African Development Community on Aug. 17. The authorities in the capital, Harare, are using the event to repair dilapidated infrastructure — like fixing roads and street lights — and build villas to be used by regional leaders at the site of a new area north of the city.

Among the activists arrested is Namatai Kwekweza, a 25-year-old pro-democracy campaigner and the inaugural winner of the Kofi Annan NextGen Democracy Prize in 2023. The prize is awarded by the late United Nations secretary-general’s foundation to young people committed to the principles of democracy.

Amnesty International has condemned the arrests, while Annan’s foundation said it was “deeply concerned” by the incident.

Kwekweza and three other activists were removed from a plane on the tarmac of the Robert Mugabe International Airport in the capital, Harare. Another 14 activists were arrested the same day for holding a protest in another town.

The four taken off the plane are being charged with disorderly conduct for being part of a courthouse protest in late June demanding the release of 77 opposition party members who have been in pre-trial detention for over six weeks.

The 77 activists were arrested at a barbecue at the house of one of their leaders. Police said they gathered “with the intent to promote violence, breaches of peace or bigotry.” A mother and her 1-year-old baby were among those detained.

President Emmerson Mnangagwa, who took over from autocrat Robert Mugabe in a coup in 2017, has been accused of cracking down on political opposition in a similar way to Mugabe, who had led the country for 37 years since independence.

Numerous opposition members, university students and labor unionists have been arrested since Mnangagwa, 81, became president.

He denies being oppressive but has warned the opposition against what he has called inciting violence. Authorities have moved to subdue any new protests ahead of the meeting of southern African leaders in Harare on Aug. 17.