An election tribunal in Nigeria is due to deliver its judgement on challenges to the outcome of February's presidential poll.
The victory of Bola Tinubu, of the All Progressives Congress, is disputed by his two main opponents.
Peter Obi and Atiku Abubakar want the court to nullify the election because of alleged irregularities.
The tribunal has the power to annul the ballot and call for a re-run - but that decision could be appealed in a higher court.
Its decision could have far-reaching implications for future elections in Africa’s most populous democracy.
However, no presidential election result has been overturned since Nigeria returned to civilian rule nearly a quarter of a century ago.