Major General Godefroid Niyombare was captured two days after announcing Mr. Nkurunziza had been toppled in the African nation, which is still recovering from an ethnically fuelled civil war that ended just a decade ago.

“He has been arrested. He didn’t surrender,” presidential spokesman Gervais Abayeho told Reuters, after earlier announcing that three other generals had also been detained.

Ethnic battles

Asked what would happen to the plotters who announced the coup when Mr. Nkurunziza was abroad, Mr. Abayeho said it was up to the justice system: “They will be held answerable.”

Burundi was plunged into deep crisis after Mr. Nkurunziza announced he was running for another five-year term.

Opponents say this violates the Constitution and a deal to end the civil war that pitted rebel groups of the majority Hutu population, including one led by Mr. Nkurunziza, against the army which was then commanded by minority Tutsis.

The army is now mixed and has absorbed rival factions, but the coup attempt exposed alarming divisions. Diplomats say the longer unrest continues the more chance that a conflict, till now been largely a struggle for power, reopens ethnic wounds.

The unrest worries a region with a history of ethnic killing, but there was little sign that tensions were easing. Troops loyal to Mr. Nkurunziza had largely calmed the streets after frequent gunfire on Thursday.

But activists called for more rallies against the President, while some Bujumbura residents said police told them they would be fired upon at if they did demonstrate.