Senegalese police clashed with supporters after the arrest of opposition leader Ousmane Sonko on Thursday, leaving one person dead in the south of the country, a police official said.

It was the first death confirmed in clashes since Sonko was arrested on Wednesday for disturbing public order as protests broke out ahead of his court appearance on a rape charge.

Sonko, leader of the opposition Pastef party and former presidential candidate, is considered a key potential challenger for President Macky Sall in elections in three years.

One person was killed in clashes on Thursday in Bignona town, in the southern Casamance region, the police official said.

“We still don’t know the cause, it is under investigation,” said the official who asked not to be identified.

Four police were also injured in the clashes.

Sonko’s arrest has triggered the worst clashes seen in Dakar in years in a West African country known for its stability.

Dozens of students were still holed up in a Dakar’s Cheikh Anta Diop university on Thursday, where they tossed concrete blocks at police, who responded with tear gas and stun grenades, an AFP reporter at the scene said.

Sonko was transferred on Thursday evening to a Dakar courthouse where his case will be heard by a judge.

Hundreds of people had followed his motorcade on Wednesday, sounding horns and singing before clashes erupted and Sonko was arrested before reaching the court.

Interior Minister Antoine Felix Abdoulaye Diome said Sonko had been arrested over a ban on gatherings because of the coronavirus and violating a traffic plan put in place.

“Everyone has to comply. Others have done the same. I wonder why there would be an exception,” he told RFM radio.

Sonko also denies the rape charges filed against him last month by an employee at a salon where he received massages.

A 46-year-old devout Muslim, Sonko is frequently critical of Senegal’s ruling elite and is popular with young supporters.

He accuses Sall of conspiring to sideline him ahead of the 2024 elections.

Violence also broke out Wednesday in other cities including in Casamance, where Sonko’s father is from and where he has a strong following.

Sonko ran against the president in the 2019 vote, but finished third in a race that delivered the incumbent a second term.

Presidents in the former French colony are limited to two consecutive terms, but Sall launched a constitutional review in 2016, raising suspicions he intends to run again.