(Bloomberg) -- The Nigerian politician who ran an upstart presidential campaign from outside the two main parties vowed to overturn the election result in court after he finished in third place.

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“We won the election and I will prove it to Nigerians,” Peter Obi told reporters in the capital, Abuja, on Thursday. The Labour Party’s candidate reaffirmed remarks made the previous day by his running mate, Datti Baba-Ahmed, who vowed to submit a legal challenge to the Feb. 25 vote won by Bola Tinubu.

Lawyers for the main opposition Peoples Democratic Party are studying the election results and party will act on their advice, leader Atiku Abubakar said at a separate briefing Thursday, adding that the “processes and outcome of the elections were grossly flawed and must be challenged by all of us.” The courts rebuffed his efforts to reverse the result of the last election in 2019 after he lost to President Muhammadu Buhari.

Obi said his supporters asked him to fight Tinubu’s victory in court. “I am going to go where I am directed to go,” he said.

The LP must file its petition within 21 days of the result that was announced on March 1.

The ruling All Progressive Congress’ Tinubu received about 35% of the votes, beating the PDP’s Abubakar, who tallied 28% of the ballots, and Obi, who garnered around 24%, according to the electoral commission. The PDP and LP boycotted the collation process, alleging “monumental disparities” between the official results and the data available to their polling agents.

The presidential race “will go down as one of the most controversial elections ever conducted in Nigeria,” Obi said. “The good and hardworking people of Nigeria have again been robbed by our supposed leaders who they trusted,” he said.

Tinubu is due to take over from Buhari at the end of May after a three-month transition.

(Updates with Abubakar comment in third paragraph)

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