ROME, April 12 (Xinhua) -- Italian center-left leader Romano Prodi said on Wednesday that he was not worried about an overturn of parliamentary election results, insisting that his narrow victory was safe.

    "It is a completely straightforward victory," Prodi told foreign reporters based in Rome. "We have a majority in both the Chamber of Deputies and the Senate and we will work and govern the country well."

    Italian Prime Minister Silvio Berlusconi challenged Prodi's victory and demanded checks on spoilt and disputed voting slips and even a possible recount.

    He also talked of "irregularities" but refused to give details.

    Italian President Carlo Azeglio Ciampi said the voting had been"orderly and regular, according to Italian democratic tradition."

    But the center-right found that 18 boxes of ballot slips bearing the Interior Ministry stamp were abandoned on Wednesday morning near a Rome school used as a polling station during the vote on Sunday and Monday, Italian media reported.

    A member of Berlusconi's Forza Italia was quoted by local mediaas saying, "this is extremely serious... Forza Italia demands clarification so that the doubts and fears that are intensifying over the legality of these elections can be put aside."

    Center-left Rome Mayor Walter Veltroni also said the incident was "very serious."

    Local officials speculated that the boxes had been thrown away by mistake. Rome prosecutors have started an investigation into the event.

    Italian electoral officials said the review of the disputed ballots would be completed by Thursday evening. Enditem