Center-left leader Romano Prodi said Friday the counts of contested ballots were confirming his narrow parliamentary election victory, and opposition leaders pleaded with Premier Silvio Berlusconi to end his challenge.

The judges "are continuing the checks, as is their duty" Prodi was quoted as saying by the Italian news agencies. "And as was expected, they are not leading to any change. Victory is confirmed."

Berlusconi has refused to concede and has demanded judicial authorities check "one by one" at least 60,000 polling stations — almost the total amount in the country and more than 1 million annulled ballots.

But by law, only ballots that are contested can be checked by the judges. All other complaints regarding blank, null or otherwise irregular ballots must be taken up by legislative commissions formed once the new parliament convenes.

Members of his coalition asked Berlusconi to stop challenging the election results.

"I want to invite the premier to lower his tone and stop what appears to be a real strategy of tension, an undermining of the electoral victory that increases the bitterness" said Massimo D'Alema, a former premier and a leader of the Democrats of the Left opposition party, in an interview in Italy's leading daily, Corriere della Sera.

Official returns gave Prodi's center-left coalition the majority in both houses of parliament in the April 9-10 elections — but the margin was a mere 25,000 votes in the lower Chamber of Deputies.

As is routine after an election, judges were examining 43,000 ballots from the chamber that were not immediately included in the overall official count because there were possible problems, but not enough to invalidate them outright.

Newspapers reported Friday that the number of contested ballots in the chamber was much lower than the count originally provided by the Interior Ministry, which mistakenly included ballots that had already been invalidated.

The Interior Ministry said it had nothing new to say, and referred to a statement Thursday night in which it listed the same numbers of contested ballots but said that "the electoral results released by the Interior Ministry are temporary and not official."

Judges also were examining another 39,000 ballots for the Senate vote. There were some closely fought regions that could swing the overall number of senators in favor of Berlusconi's coalition. In the Naples region, Campania, Prodi's forces won with 49.6 percent to 49.1 percent for Berlusconi.

Newspapers and politicians say checks of contested ballots so far indicate the ballots would not change the balance. Experts say that it is unlikely, statistically and historically, that either side would win 50 percent of the contested ballots.

Late Thursday, Prodi's office said he had received calls of congratulations from German Chancellor Angela Merkel, British Prime Minister Tony Blair and Brazilian President Luiz Inacio Lula da Silva.

According to the statement, Merkel told Prodi she looked forward to working with him. It said Blair and Prodi held "a long, friendly and cordial conversation."

It could be weeks before Prodi takes office. The outcome of the election must be approved by Italy's highest court, and it is up the president to give the head of the winning coalition a mandate to form a government.

However, the president's term ends in mid-May, and the current president, Carlo Azeglio Ciampi, has said he would leave the decision up to his successor.

Parliament has until May 13 to elect a new president, meaning a new government would not be formed until mid-May at the earliest.