Heavy security has been deployed across Nigeria's capital, Abuja, where judges have began reading their verdict on a case challenging the election of President Bola Tinubu.

Opposition candidates moved to court seeking to overturn the outcome of the presidential election claiming fraud and irregularities.

Tinubu won 37% of votes in the February 25 election, beating the Peoples Democratic Party's Atiku Abubakar and Labour party's Peter Obi.

Soldiers and police have mounted roadblocks on major roads in the city, as well as outside the court where supporters of the three politicians have formed a crowd.

Police had earlier said they were prepared to maintain law and order.

Any decision on Wednesday appears unlikely to be the final stage of legal wrangling over the election, as lawyers say parties can appeal to the Supreme Court for a final verdict.

Despite repeated challenges to past elections, no court has overturned a presidential vote in Nigeria since its return to democracy from military rule in 1999.

Tinubu's government has appeared confident, highlighting the judiciary's integrity.