Milan, December 5 - The chief executive of Europe's largest oil contractor resigned Wednesday amid an investigation into allegations of corruption related to contracts in Algeria. Chief executive officer Pietro Franco Tali of Saipem was replaced by Umberto Vergine, as Milan prosecutors probe alleged corruption offences. Two managers have also been suspended from Milan-based Saipem, Europe's largest oil contractor by market value. The company's board also ordered an internal investigation using outside consultants. Tali, in his resignation statement, said he was not "in any way involved" in the case, bud said his resignation would best serve the company.