A prominent political rival of Burundi's president has escaped from prison where he was serving 13 years on charges of endangering state security, the justice ministry said on Tuesday.
Hussein Radjabu fled with six others including three police officers who were guarding the jail, justice ministry spokesman Eliason Bigirimana said.
The reported escape comes as political tensions mount before a run for a third term, while opponents say he can only serve two.
Former rebel leader Radjabu was a founder of Nkurunziza's ruling Hutu CNDD-FDD party, but was later ousted from its leadership, arrested in 2007 and sentenced a year later.
Commentators say Radjabu, who once controlled the party's finances and intelligence arm, continued to be supported by senior party members after his detention.
"Radjabu left Bujumbura central prison on Sunday night around 10:30 (2030 GMT). He was helped by the chief police officer in charge of the prison security,'' Bigirimana told a news conference. "Investigations continue, but everything shows that he has well prepared his escape.''
Nkurunziza has not said that he will run, but civil society organizations have said they will call for massive street protests if he declares his candidacy for a third term.