Nigeria's presidential candidate Peter Obi, who came third in the February 25 election won by the ruling party's Bola Tinubu, announced Thursday that he would take his case to court to challenge the results.
"We will explore all legal and peaceful options to get our mandate back. We won the election and we will prove it to Nigerians," Obi of the Labour Party (LP) said at a press conference in the capital Abuja.
According to the Electoral Commission (Inec), Bola Ahmed Tinubu, 70, won the presidential election with more than 8.8 million votes, or 36% of the vote, at the end of a poll contested by the opposition, which denounced "massive" fraud.
The candidate of the All Progressives Congress (APC), the former governor of Lagos, will succeed the outgoing president Muhammadu Buhari, 80, who has been criticized from all sides for his deplorable record and his two terms marked by an explosion of poverty and insecurity.
Peter Obi, 61, a youth favourite, came third with 25% of the vote, a first in Nigeria's democratic history for an outsider from the two main political groups. The second-place winner is former vice-president Abubakar (29%) of the main opposition party (PDP).
The election, which was generally peaceful, was marked by delays in the counting of votes and major failures in the electronic transfer of results, angering many voters and opposition parties who claim that the votes were massively rigged.
"This election will go down as one of the most controversial ever held in Nigeria," Obi said.
"The Nigerian people (...) have once again been robbed by our supposedly trusted leaders.
In the past, elections in Africa's most populous country have often been marred by allegations of fraud and violence.
On Wednesday, Mr. Tinubu called on his opponents to "team up together": "I ask you to join us so that we can start rebuilding our national home together.
Nicknamed the "godfather", the "kingmaker" or the "boss" for his considerable influence, Mr. Tinubu has been repeatedly accused of corruption during his career, without ever being convicted.
Candidates who want to contest the election have 21 days after the results are announced to file a lawsuit.