The unidentified top Siemens executive alleges Pierer knew more about the illicit dealings than he has admitted and personally had knowledge of a $10 million bribe related to a project in Argentina, Der Spiegel reported Saturday.

The Siemens Business Services manager said while other managers in the company expressed concerns with similar payments, Pierer allegedly disregarded such advice.

Another Siemens manager previously alleged that the engineering company had paid multiple bribes to the Interior Ministry as part of the Argentine project.

Pierer has maintained he was unaware of the reported bribes paid by the German company and has denied allegations he told his managers to act as "soldiers of Siemens" in those efforts.

Der Spiegel said Pierer had served as a technology adviser to German Chancellor Angela Merkel, but the government official said Thursday she would no longer be using Pierer's services.