BUJUMBURA, Burundi - Burundi's main opposition leader Agathon Rwasa on Saturday denounced the third consecutive term win by President Pierre Nkurunziza and demanded fresh elections.
Rwasa, who won 18.99 per cent of the vote despite saying he was unable to properly campaign, said he would not oppose the formation of a unity government if its "primary mission is to prepare free and democratic elections."
Nkurunziza's candidacy was condemned as unconstitutional by the opposition and provoked months of protests and an attempted coup in mid-May.
His victory - taking 69.41 per cent of the vote in Tuesday's polls and handing him an immediate first-round victory - could trigger donor sanctions against the already impoverished nation.
There are also widespread fears the country, situated in the heart of central Africa's troubled Great Lakes region, could be plunged back into civil war.
Although eight candidates were on the ballot for the presidential poll, most had withdrawn from the race after the closure of most independent media prevented them from campaigning.
The election commission insisted however that turnout in the polls was a healthy 73.44 per cent.
US Secretary of State John Kerry, in a statement late Friday, said the elections were "neither credible nor legitimate" and called for peaceful talks between rival parties.
"Burundi's presidential electoral results is the culmination of a deeply flawed electoral process marked by violence and a disregard for the civil and human rights of the citizens," Kerry said.
Election observers from the East African Community, which tried but failed to mediate a solution to the crisis, also denounced the polls.
Meanwhile election commission sources said Nkurunziza's ruling CNDD-FDD party had won 34 out of 36 senatorial seats in elections held Friday, with the remaining two seats won by allied parties.
Official results are due early next week.
Anti-Nkurunziza protests have rocked the capital and some rural areas since late April and have been violently repressed, leaving at least 100 people dead and countless of others wounded or in detention.
Many opponents have also fled - joining an exodus of more than 150,000 ordinary Burundians who fear their country may again be engulfed by violence.
In mid-May, rebel generals attempted to overthrow Nkurunziza in a coup, which failed. They have since launched a rebellion in the north of the country.