Mali's constitutional court has announced final results from the first round of presidential elections on April 28.

Results were released by Mali's constitutional court just days before Malians are due to return to the polls on Sunday for a second round to pick a leader to succeed outgoing President Alpha Oumar Konare.

Their choice on Sunday, as confirmed by the court Thursday, will be between former transition leader Amadou Toumani Toure - who came in first place in the first round of voting - and former cabinet minister Soumaila Cisse, who finished second.

The constitutional court's job was to ratify the tally from the April 28 polling. In doing so, the nine-member panel reviewed more than 30 complaints of irregularities, ranging from problems with voter registration cards to accusations of fraud and manipulation of the tallies at polling stations.

Among those who filed complaints was the candidate who came in third, Ibrahim Boubacar Keita - a former prime minister. Mr. Keita accused the government of manipulating the vote to keep him out of the second round. Government officials denied the claim.

Court officials on Thursday announced that nearly one-quarter of all votes cast were invalidated because of irregularities that included duplicated voter registrations. Under Mali's laws, results issued by the constitutional court cannot be appealed.

The balloting on April 28 was carried out in an atmosphere of calm. Tension rose, however, in the days following as officials took much longer than they had said they would to release the results.

Mali, one of the world's poorest nations, has been held by the international community as a model for democracy in sub-Saharan Africa. Western leaders have praised President Alpha Oumar Konare for not attempting to change the constitution in order to remain in power after the expiration of his maximum-allowed two, five-year terms.