A Burundi general who was part of a failed coup attempt in May said his group was still working to oust President Pierre Nkurunziza, accusing him of stoking ethnic divisions in a country still trying to recover from civil war.
"At that time (in May), we just failed to remove Nkurunziza from power," General Leonard Ngendakumana told Reuters in an interview on Thursday outside Burundi. "The aim is still there."
The president, whom Ngendakumana served as a senior intelligence officer in government and during the civil war as a rebel fighter, has plunged Burundi into its deepest political crisis for a decade by seeking a third five-year term.
Opponents say the president's re-election bid violates the constitution and a peace deal that in 2005 ended the civil war, which had pitted majority Hutu rebel groups, like the one led by Nkurunziza, against the army, then led by minority Tutsis.
Nkurunziza cites a court ruling saying he can run again.
Government officials dismiss charges that Nkurunziza, who has Hutu and Tutsi parents, has divided the nation on ethnic lines and say his opponents are stirring trouble because they fear defeat in a presidential vote, set for next week.
Ngendakumana, 46, who asked that his precise location was not disclosed, said the president and his allies were behind stoking ethnic tensions and were arming the ruling CNDD-FDD's youth-wing Imbonerakure, widely seen as a Hutu force.
"This situation can lead to a genocide," he said.
Next door Rwanda, with the same ethnic mix, suffered a genocide in 1994 that killed 800,000, mostly Tutsis as well as moderate Hutus.
The United Nations, African states and Western nations have also expressed alarm about the arming of Imbonerakure.
More than 140,000 Burundians have fled the country. U.N. spokesman Stephane Dujarric said on Thursday that many refugees had cited "Imbonerakure militia as the main threat".
CNDD-FDD officials deny charges its youths have been armed. They say it is a mixed ethnic group that is devoted to political campaigns and other party activities.
Ngendakumana, a Hutu who was fired from his intelligence post in February after helping write a report for the president advising him not to run again, said international pressure on the president had failed.
"The only way to reach this objective is to use force," he said, adding that he was working with coup leader General Godefroid Niyombare and in "organising ourselves in military units" to help protect people from police or Imbonerakure.
Protesters have regularly clashed with police.
Presidential spokesman Gervais Abayeho said anyone threatening Burundi's security "will meet the full force of our defence and security forces."
Ngendakumana said the international community could ratchet up the pressure by delivering on threats to impose sanctions.
The United States and the European Union have threatened sanctions against those it blames for stoking violence.