Political outsider says says he will prove he won, after official result awarded victory to ruling party’s Bola Tinubu

The third-party candidate Peter Obi said he would challenge the outcome of Nigeria’s fiercely fought presidential elections after official results awarded victory to the ruling party’s candidate, Bola Tinubu.

“We will explore all legal and peaceful options to reclaim our mandate. We won the election and we will prove it to Nigerians,” Obi, the Labour party candidate, told reporters on Thursday in the capital, Abuja.

Final tally not expected until middle of next week as polling system hit by significant technical problems

Nigeria is in the midst of a tense wait as election authorities count tens of millions of votes that will determine who will become president in Africa’s most populous country and control its national assembly.

Voting on Saturday was marred by widespread delays and some scattered violence but fears of widespread chaos proved unfounded.

Vote largely peaceful in Africa’s largest economy but half of polling stations opened late due to technical issues

Polls have shut in Nigeria, after tens of millions cast their votes to decide a tight and unpredictable contest for the presidency and parliament of Africa’s most populous nation and its biggest economy.

The opening of more than half of all polling stations was delayed by at least an hour with many others suffering problems with new voting technology, civil society groups said. There was some sporadic violence across the country, including a suspected attack by Islamic extremists and some disruption by hired thugs.

Bola Ahmed Tinubu remains frontrunner for president but a new voice has captured the youth vote

The posters lining the roads of Lagos show the face of a smiling, bespectacled 70-year-old above a slogan promising renewed hope. Vote for Bola Ahmed Tinubu, pedestrians and drivers negotiating the chaos of the Nigerian commercial capital are told. Vote for peace, justice, unity.

On Saturday, the 6 million inhabitants of Lagos who have collected their voting cards will have to decide whether Tinubu and his ruling All Progressives Congress might fulfil any of these promises. So too will another estimated 81 million voters among the 220 million inhabitants of Africa’s most populous country. Their collective decision will determine the result of Nigeria’s seventh presidential elections since the end of military rule in 1999.