Atiku Abubakar

Nigeria's electoral commission says it will comply with a Supreme Court ruling and put Vice President Atiku Abubakar on the ballot for Saturday's presidential election.

A commission spokesman, Phillip Umeadi, gave no details on how officials will put Abubakar's name on 60 million ballots with just four days to go before the vote. The spokesman said "the logistics are being put in place."

The electoral commission tried to disqualify Abubakar based on allegations of corruption. Abubakar - the presidential candidate of the opposition Action Congress party - denies the charges.

Election observers have questioned whether Nigeria can hold a free and fair presidential vote, after state elections last Saturday were marred by allegations of fraud and violence that reportedly killed about 50 people.

Police have declared a nationwide ban on all political rallies in an effort to prevent further violence.

More international observers have arrived to monitor the presidential election, including former U.S. Secretary of State Madeline Albright.

Umar Yar'Adua

Nigerian voters are choosing a successor to President Olusegun Obasanjo, who is required to step down next month after serving two four-year terms. The ruling party has nominated a state governor, Umar Yar'Adua, as its candidate.

Opposition challengers include Vice President Abubakar and former army general Muhammadu Buhari, a former military ruler of Nigeria in the mid-1980s. Nigerian opposition parties are to meet today to discuss uniting behind a single candidate for the poll.

The official results from the state polls show the ruling People's Democratic Party winning a large majority of governor seats. However, opposition parties have rejected the results as fraudulent.

U.S.-based Human Rights Watch says its monitors saw supporters of the ruling party stuffing ballot boxes in Rivers state and other areas.

Some information for this report was provided by AP and Reuters.