Dozens were killed before the July 21 election, which saw weeks of demonstrations, a failed coup and clashes between rebel soldiers and the army.
Burundi's electoral commission will announce on Friday the winner of a presidential poll marred by violence and a boycott by the opposition, with President Pierre Nkurunziza widely expected to win a new term in office.
Nkurunziza's decision to seek a third term had plunged the small east African nation into its biggest crisis since an ethnically charged civil war ended in 2005. The opposition says Nkurunziza's bid violates the constitution.
Dozens were killed before the July 21 election, which saw weeks of demonstrations, a failed coup and clashes between rebel soldiers and the army. More then 175,000 people have fled to neighbouring countries to seek refuge.
Regional leaders and Western diplomats fear Burundi could slide back into civil war if tensions are not resolved. That is a frightening prospects for a region scarred by the 1994 genocide in neighbouring Rwanda, where about 800,000 Tutsis and moderate Hutus were killed. Burundi has a similar ethnic makeup.
Pierre Claver Ndayicariye, the president of the electoral commission (CENI), told Reuters the results would be announced during a CENI press conference scheduled for 1500 local time (1300 GMT).
Few expect Nkurunziza to lose. The names of rival candidates were printed on ballot papers, but the opposition boycotted the race and called for voters to do the same.
The African Union and the European Union have said the poll cannot be free or fair under the current circumstances, citing insecurity and shutdowns of private media by the government.
The United States has threatened to cut aid and the European Union said it was preparing sanctions.
Agathon Rwasa, leader of the opposition Amizero y'Abarundi coalition, said a unity government should be formed immediately to stop the nation of 10 million people slipping into conflict. He also called for a new election within a year.
A presidential advisor said a unity government would not be opposed. But he rejected as "impossible" the idea of cutting short any new mandate.
Nkurunziza's supporters say the president can seek a third term in office as a constitutional court cleared his candidacy.
The United Nations has warned more than half a million Burundians may end up leaving the country is the crisis persists.