Alexis Sinduhje is accused of insulting President Pierre Nkurunziza (above)
The leader of Burundi's opposition Movement for Security and Democracy has been imprisoned, accused of insulting the president.
Alexis Sinduhje was sent to the central prison in the capital, Bujumbura, after appearing briefly before a magistrate.
Police had already detained him for nine days for holding an unauthorised meeting with about 40 followers.
By sending him to prison, Burundi defied appeals from the EU and the US for his release.
Mr Sinduhje's lawyer said at the court appearance that the charge of insulting the president was unexpected.
The BBC's Prime Ndikumagenge reports from Bujumbura that Mr Sinduhije is best known for having founded a popular private radio station, the African Public Radio.
He has also received several international awards for his investigative reports and his campaigning for freedom of speech.
Many people in Burundi regard his arrest and detention as being politically motivated, our reporter says, coming less than two years before the next general elections.
Mr Sinduhije is one of several opposition and civil society figures in the central Mpimba prison.
Ex-rebel Pierre Nkurunziza was elected president in 2005 under a deal to end years of conflict between the Tutsi army and Hutu rebels.
About 300,000 people were killed in more than a decade of civil war.