Peter Obi, the presidential candidate for the Labour Party, asserted on Thursday that he had won last Saturday's poll and was prepared to present the evidence.
Bola Tinubu of the All Progressives Congress won the presidency in a contentious election that he said was rigged to produce predetermined outcomes.
After receiving 8,794,726 votes to win the 2023 presidential election, Tinubu, a former governor of Lagos State, was named the new president.
In the International Collation Centre in Abuja in the wee hours of Wednesday, INEC Chairman Professor Mahmood Yakubu declared Tinubu the winner.
But on Thursday, Obi stated at a global press conference in Abuja that the election did not meet the criteria and could not be deemed genuine.
The former governor of Anambra State stated that Nigerians had been cheated out of their rightful choice. He added that he would seek justice in court and was prepared to contest the results until he could establish his case.
"The election that we just watched was done as planned, and the results were announced. Contrary to what we were promised, there is a blatant violation of electoral laws and regulations.
The minimum requirements for a free, fair, transparent, and credible election were not met by this election. It will be remembered as one of the most divisive elections ever held in Nigeria.
"Our putative leaders, whom they trusted, have once more looted the good and hardworking people of Nigeria," he stated.
Let me reassure the decent citizens of Nigeria that we will investigate every legal and peaceful alternative to restore our mandate. I'll show Nigerians that we won the election, Obi declared.
The former governor stated that he thought it was crucial for Nigeria to sanitize the process by which people are appointed to any office.
The way people enter the workplace is significantly more essential and significant than anything else they do there, according to Obi.
"I think the way you get to the office ought to be fantastic if you're going to answer your excellency.
"In order to develop the moral authority and confidence needed to lead, we must now insist that we act morally. As you are aware, when we behave slyly and deliberately in manipulating the rule of law and suppressing the will of the people, the structure of society starts to regress.
He claimed that after successfully contesting multiple election results, he would approach the court with the conviction that he would be granted justice.
The former governor declared, "There is a court for this, and they have asked me to go there. I will go there.
When asked if he felt under pressure, he quips that no one could make him feel under pressure for calling out the rascal.
Please be reassured that this is not the conclusion but rather the start of a journey for the creation of a new Nigeria, he said.
"Datti and I are still steadfastly devoted to building a new Nigeria that is based on integrity, openness, fairness, justice, and equity. The process is where all of the aforementioned begins.
We must proceed through this darkness, he continued. The foundation of criminality cannot be eliminated suddenly.
"All we have to do is demonstrate our commitment and tenacity. I will lead the charge and fight through the night until dawn, Obi promised.