Burundi's election commission is expected Monday to declare Evariste Ndayishimiye the country's next president, with all signs showing the ruling party's candidate on track for victory following last week's poll.
The National Independent Electoral Commission will unveil the outcome of the presidential and legislative races at 1200 GMT.
Local government results are also expected Monday.
Partial results already announced on state media indicate that Ndayishimiye, an army general from the governing CNDD-FDD who was hand-picked to succeed outgoing President Pierre Nkurunziza, has an insurmountable lead over his opponents.
Agathon Rwasa, the main opposition leader, has alleged foul play, saying early numbers showing his CNL party heading for a bruising defeat are a "fantasy".
According to a tally by AFP covering 105 of 119 municipalities, Ndayishimiye won an outright majority in 101, and in at least one secured 99.9 percent of the vote.
In the four communes where he was defeated, Ndayishimiye attracted a support rate of no less than 43 percent.
Rwasa and his CNL, meanwhile, managed just 24.6 percent in Kabezi, a historic stronghold in western Bujumbura for the opposition party, which says some of its officials were harassed and detained on voting day.
The veteran politician attracted large crowds throughout his campaign, as did the ruling party, despite concerns about the coronavirus pandemic.
Analysts predicted the presidential race would come down to a contest between Rwasa and Ndayishimiye, the strongest of seven candidates.
A foreign diplomat in Burundi, speaking anonymously, expressed strong doubts about the official result but said it was not surprising.
"We were expecting it to happen like this. Nobody could imagine for a second that the CNDD-FDD and its generals would cede power in any way," the diplomat said.
Burundi, which the World Bank ranks among the world's three poorest countries, has been under sanctions from its major donors since 2015, when Nkurunziza's decision to run for a third term as president triggered violent unrest and political chaos.
At least 1,200 people have died and 400,000 have fled the country in violence that continues to this day.
So far this year's election has not seen a repeat of that violence.
Rwasa has already hinted he would not take to the streets in protest and would appeal to the Constitutional Court, though he considers the process imperfect.
Tensions were high during the campaign and on voting day, when both sides accused the other of fraud and several CNL officials were arrested.
Burundi is tightly controlled by the ruling party and its youth wing, the Imbonerakure, have been accused of a forceful crackdown against the government's critics in the aftermath of 2015.
If the election commission announces Ndayishimiye the winner as expected, he will be sworn in for a seven-year term in late August, when Nkurunziza's term ends.
It is unclear whether Ndayishimiye would be able to rule free from interference by Nkurunziza, who in February was elevated by parliament to the rank of "supreme guide for patriotism" and will remain chairman of the party's highly influential council of elders.
The final election results will be declared by the Constitutional Court on June 4.