Uganda's President Yoweri Museveni, will fly to Burundi on Tuesday to mediate between government and opposition leaders, an official said, a personal intervention underlining the scale of regional alarm over an increasingly violent stand-off.
Opposition politicians have accused Burundi's president of violating the constitution by running for a third term in July 21 elections, and have boycotted the vote and called a series of protests.
Western diplomats have warned that the dispute could collapse into conflict after a general involved in a failed coup said he was mobilising troops and armed clashes erupted in the north of a central African nation still scarred by civil war.
Salvator Ntacobamaze, the permanent secretary in Burundi's cooperation ministry, told Reuters the details of talks had not been finalised but Museveni would arrive on Tuesday.
Burundi's President Pierre Nkurunziza has shrugged off calls from Washington and other regional and Western powers for him not to run, saying his candidacy is backed by a court ruling.
General Leonard Ngendakumana, a leader in the abortive May 13 putsch, told Reuters last week his group was still working to oust Nkurunziza, accusing him of stoking ethnic divisions..
Ngendakumana, a former intelligence officer, acknowledged late on Sunday his men had carried out attacks over the weekend in northern areas bordering Rwanda and the Democratic Republic of Congo.
He denied government reports that rebels had died, and that they had raided Burundi from Rwanda. "Rather so many government soldiers died in the fighting," he said.
A flare-up in Burundi risks repercussions well beyond the borders of the tiny nation of 10 million people and will create fresh instability in a region with a history of ethnic conflict.
More than 145,000 Burundians - almost 1.5 percent of the population - have already fled across borders. The crisis could drag in regional players, like Rwanda, a victim of a 1994 genocide that has vowed not to let it happen again in the area.