What you need to know:
- The strongest opposition candidate, Agathon Rwasa, came in a distant second with 24.19 per cent of the votes.
- Burundi is tightly controlled by the ruling party.
- Nkurunziza has been in power since 2005, and his final years in office have been wracked with turmoil.
Burundi's leading opposition party will start filing challenges to election results as early as Wednesday, a lawmaker as calm reigned in the commercial capital a day after the ruling party's candidate was named winner of the presidential contest.
Evariste Ndayishimiye, a former army general chosen by the powerful CNDD-FDD governing party as heir to outgoing President Pierre Nkurunziza, won the May 20 poll with 68.72 percent of the vote, according to results announced Monday.
The strongest opposition candidate, Agathon Rwasa, came in a distant second with 24.19 per cent, but his National Freedom Council (CNL) has rejected the results and accused the CNDD-FDD of fraud.
CNL officials were still preparing appeals Tuesday in polls which also involved legislative and municipal contests, said a party lawmaker, who spoke to AFP anonymously.
The party has until Thursday to formally contest the presidential outcome, although the appeal will "probably" be ready Wednesday along with challenges in lower-level races, the lawmaker said.
Many shops and bistros closed Monday evening after the results were announced, but life largely returned to normal Tuesday in Bujumbura, the commercial capital, and elsewhere in the country.
Burundi is tightly controlled by the ruling party and its youth wing has been implicated in a forceful crackdown against the government's critics.
No foreign observers were allowed into Burundi to keep an eye on the election, which went ahead with scant regard for the coronavirus outbreak following a tense campaign marked by violence and arbitrary arrests.
"We feel that people are resigned. We also feel a deep disappointment because everyone says their victory was stolen from them but they know they can’t do anything," said a bank employee who spoke to AFP on condition of anonymity.
Nkurunziza has been in power since 2005, and his final years in office have been wracked with turmoil.
His third-term election run in 2015 sparked violence which left at least 1,200 dead and pushed 400,000 to flee the country.
While some observers feared Rwasa would urge his supporters to take in protest after results were announced, he appears committed to a legal challenge, said Richard Moncrieff of the International Crisis Group, a conflict-prevention organisation.
Rwasa acted similarly during the unrest of 2015, unlike other members of the opposition, Moncrieff noted.
"He did not choose exile or armed struggle. He obviously made a personal choice," Moncrieff said.
The CNDD-FDD also defeated the CNL by a similar margin in the legislative elections.
In another sign that the CNL will stick to a constitutional path, its members participated in a meeting Tuesday with the only other opposition party to secure seats.
The constitution requires that ethnic Hutus make up 60 percent of the National Assembly and ethnic Tutsis 40 percent, and 30 percent of the body must be women.
Some reshuffling will need to take place to honour the quotas.
Wary of ratcheting up tensions, the CNDD-FDD has called on its supporters to refrain from "provocation" and to hold off a few days before celebrating its victory.
Yet the youth wing, known as the Imbonerakure, has already begun settling scores in the northwest province of Citiboke and elsewhere, witnesses told AFP.
"They tell us that we committed a grave error voting for (the CNL), that we are going to pay dearly and that we must not submit if we want to live in peace in this country," a Citiboke resident said.
Ndayishimiye is expected to be sworn in for a seven-year term in late August, when Nkurunziza's term ends.
The 52-year-old is set to inherit a deeply isolated country, under sanctions and cut off by foreign donors, its economy and national psyche damaged by the years of unrest.
It remains to be seen how much influence Nkurunziza will exert and how freely his successor can reign.
Nkurunziza was this year elevated by Burundi's parliament to the rank of "supreme guide for patriotism" and he will continue to be chairman of the ruling party's powerful council of elders.
In a Twitter post Tuesday morning, Nkurunziza congratulated his successor on a "large victory".
"I warmly congratulate the President-elect Gen. Major Evariste Ndayishimiye for his large victory which confirms that the great majority of Burundians adhere to the projects and the values he embodies," the outgoing president wrote.
"We are privileged witnesses to history. May God bless Burundi!"
Burundi's main donors, which imposed sanctions on the country in 2015, have not yet reacted to Ndayishimiye's victory.
A diplomat stationed in Bujumbura said donors would likely welcome the arrival of a "new face" who is seen as less dogmatic than his predecessor.