ABUJA, Nigeria (UPDATED) – Muhammadu Buhari was on Wednesday, February 27, re-elected Nigeria's president after a delayed poll that angered voters and raised political temperatures, but the opposition immediately vowed to challenge the "sham" result in court.
It was the second victory at the ballot box for Buhari, a one-time military ruler who was first elected in 2015 to lead Africa's most-populous nation and top oil producer.
With ballots counted in all of Nigeria's 36 states and the Federal Capital Territory (FCT), Buhari triumphed with some 15.2 million votes over his nearest rival Atiku Abubakar, who trailed by nearly 4 million votes.
"Muhammadu Buhari...is hereby declared winner and is returned elected," Mahmood Yakubu, chairman of Nigeria's Independent National Electoral Commission, (INEC) announced early Wednesday.
However, Abubakar rejected the result of the vote, which has been marred by claims of rigging and corruption.
"If I had lost in a free and fair election, I would have called the victor within seconds of my being aware of his victory to offer not just my congratulations, but my services to help unite Nigeria by being a bridge between the North and the South," he said in a statement Wednesday.
"I hereby reject the result of the February 23, 2019 sham election and will be challenging it in court."
Buhari, aged 76, meanwhile, thanked Nigerians for re-electing him for the next 4 years, saying he was "deeply humbled and profoundly grateful."
Addressing supporters and party leaders at his All Progressives Congress (APC) campaign headquarters, Buhari called his win "another victory for Nigerian democracy."
"The new administration will intensify its efforts in security, restructuring the economy and fighting corruption," he said.
'Up we go!'
Supporters had gathered outside the party's offices in the capital Abuja late Tuesday, February 26, as it became clear that Buhari had an unassailable lead, dancing and singing "We're popping champagne."
Vice President Yemi Osinbajo appeared in a video clip singing "Up we go!" in a reference to Buhari and his "Next Level" campaign slogan.
But there were none of the spontaneous street parties that marked his victory 4 years ago, when he became Nigeria's first opposition candidate to beat an incumbent president.
In 2015, president Goodluck Jonathan won plaudits for conceding to Buhari in a phone call, when the results indicated he could not win.
The concession is acknowledged as having prevented a repeat of the deadly violence that marred previous elections in Nigeria.
Yet Abubakar has rejected the results of the vote which took place on Saturday, February 23, after a one-week delay.
Following the delay, the APC and PDP intensified their war of words, each accusing the other of conspiring with INEC to rig the result.
The PDP claimed data from handheld devices used to authenticate voters' identities at nearly 120,000 polling units had been altered in favor of the ruling party.
It called for the results in at least two states to be re-run and for a reversal of the cancellation of tens of thousands of "valid, legal" votes elsewhere.
Observers noted challenges with the electoral process but called the result credible.
A PDP spokesperson said evidence for a legal challenge was being compiled to be put to the Presidential Election Tribunal, set up by Nigeria's Supreme Court. "The documents are still being drafted," said Boladele Adekoya.
Weeks before the election Buhari sparked controversy by suspending the Supreme Court Chief Justice, Walter Onnoghen. He was accused of failing to declare foreign currency bank accounts, in breach of rules governing public officials.
As head of the Supreme Court, Onnoghen would have ruled on any dispute, but it will now be overseen by the acting chief justice, Ibrahim Muhammad Tanko.
"We wait to see how independent and truthful Acting CJN panel is," spokesperson Adekoya said.
The panel, lead by the new chief justice, will adjudicate on any legal challenge to the result, with the power to overturn it.
The vote was marred by violence, including 53 deaths, according to the Situation Room, an umbrella group of 70 civil society groups that monitored polling.
Some observers reported vote-buying, intimidation and violence towards voters and officials, which have been a problem in previous polls in Nigeria.
The issues will likely prompt calls for electoral reform, including the introduction of technology capable of directly transmitting results from polling units.
A total of 72.7 million people were eligible to vote in the presidential poll as well as parliamentary elections held at the same time.