Burundi is on the brink of civil war and will need regional mediation to establish a peace process between the government and opposition to avert a new conflict, a U.S. envoy said on Thursday.

Burundi, which emerged from a 12-year civil war a decade ago, began spiralling into chaos in April when Nkurunziza’s announcement that he would seek a third term sparked months of protests in the capital Bujumbura and a failed coup.

Nkurunziza won a disputed election in July.

Thomas Perriello, the U.S. Special Envoy for Africa’s Great Lakes region, said in an interview that Burundi is “facing a real possibility of civil war,” though there is still “a window, no matter how small, to get a peace process going.”

“The most urgent thing is a regionally-mediated dialogue that will deal with the crisis itself,” he said.

Regional and world powers have grown increasingly concerned that the clashes and killings in Burundi may presage a repeat of the ethnic violence that culminated in the 1994 genocide in neighbouring Rwanda, in which 800,000 people were massacred.

But regional efforts to cool Burundi’s crisis have stumbled, despite calls by the African Union and regional East African states for dialogue.

The peace process, led by Ugandan President Yoweri Museveni and backed by the United States and others, has thus far failed to bring the two sides to the negotiating table.

“We certainly feel that President Museveni holds the ball on this right now, and therefore some of the consequences if the talks don’t get started,” Perriello said.

Critics have questioned the suitability of Museveni, who is currently running to extend his 30-year tenure as president for another five years and, as president, has overseen the scrapping of Uganda’s two-term limit and the imprisonment and abuse of opposition candidates.

Perriello said the international community has kept close watch on Burundi, and the extension of sanctions and readying of a peacekeeping force are among the options it is pursuing to prevent further bloodshed.

“We’ve learnt way too painfully from the past that you don’t want to wait until after a genocide has started to be doing things to prevent it from happening,” Perriello said.

Last month, the United States imposed sanctions on four current and former Burundi officials, citing reports of targeted killings, arbitrary arrests, and torture.

The United Nations and the African Union have also started contingency planning for the possible deployment of international peacekeepers, though “we’d frankly like to be a little further along,” Perriello said.

(Editing by Edith Honan/Ruth Pitchford)