Center-left leader Romano Prodi demanded anew Saturday that Premier Silvio Berlusconi concede defeat in Italy's tight election and apologize for alleging fraud after the number of contested ballots dwindled dramatically.

The conservative premier, however, remained defiant, describing himself late Friday as a "fighter" and an "optimist" and saying he still hoped to be declared the winner.

He also indicated in a letter published Saturday in Italy's main daily, Corriere della Sera, that he was not giving up.

"At least on the basis of the popular vote, there's no winner and no loser," Berlusconi wrote.

The official results of the contested ballot count have not been announced but were certain to confirm Prodi's narrow victory in the April 9-10 parliamentary elections after the Interior Ministry on Friday sharply reduced the number of contested ballots.

While the outcome could still be questioned, that process could take weeks to play out and Prodi urged his rival not to keep Italians waiting.

"He must acknowledge how things went, and, I believe, apologize as well after what he said about fraud," Prodi told reporters Saturday in Bologna, where he lives.

Berlusconi alleged election fraud shortly after the vote but quickly backed away from his comments.

On Friday, the Interior Ministry reduced the number of contested ballots from 80,000 to 5,200 — a figure that is insufficient to reverse the electoral result, even with a gap as narrow as the one dividing the two coalitions.

The ministry explained the confusion by saying that invalid or blank ballots had been lumped in by mistake with the contested ballots — those where the voting intentions are not clear.

The official result would formally end a week of political stalemate. Prodi's center-left won a razor-thin majority in both houses of parliament, but Berlusconi alleged irregularities and demanded thorough checks.

Berlusconi has insisted the routine count of contested ballots is not enough and wants voting reports checked from virtually every polling station in Italy. He also has alleged irregularities in the vote of Italians abroad.

But by law, only contested ballots can be checked immediately after an election. All other complaints regarding blank, null or otherwise irregular ballots must be taken up by commissions set up by the new parliament, which is due to convene on April 28.

Once checks on the 5,200 contested ballots are completed, the Italian Court of Cassation certifies the election result. It was not clear when that would happen. It could be at least Tuesday before any announcement since Monday is considered part of the Easter holiday in Italy.

In his letter published Saturday, Berlusconi also renewed an appeal he made to the opposition to create a coalition government, saying "a partial agreement, limited in time and aimed at dealing with the country's institutional, economic and international commitments should not be ruled out in principle."

He raised the possibility of a "grand coalition" earlier this week, but Prodi and other center-left leaders quickly rejected the proposal. Prodi would not need Berlusconi's party to form a government, even if his majority of elected senators in the upper house of parliament is a mere two.

Even center-right politicians have expressed skepticism over Berlusconi's stance, with some opposing any agreement with the center-left and others urging him to concede defeat.

"It seems to me that the idea of not recognizing the result is losing strength by the hour," said Franco Pavoncello, a political science professor at John Cabot University.

But the premier, Pavoncello said, was looking ahead.

"Berlusconi is trying to cut a political role for himself and his center-right coalition for after the election," he said.