Frankfurt: Qatar, Volkswagen AG’s third-largest shareholder, expects that sticking with Martin Winterkorn as chief executive officer will be difficult amid a power struggle with the carmaker’s powerful chairman, according to a report by Handelsblatt.

Qatar Investment Authority, which controls 17 per cent of VW’s voting stock, criticised Ferdinand Piech, 77, for publicly questioning the CEO’s leadership in a Der Spiegel interview on Friday, Handelsblatt reported Wednesday on its website, citing an unidentified person close to state-owned investment company.

Piech shouldn’t have made the comments without being able to present an alternative that’s backed by the supervisory board, according to the Handelsblatt article. A representative for Qatar Investment Authority declined to comment on the report.

Unions and other key power players at Wolfsburg, Germany- based Volkswagen expressed their support for the 67-year-old Winterkorn. Qatar’s holding ranks after the stakes owned by the Porsche and Piech families and the company’s home state of Lower Saxony.

Winterkorn’s future at the world’s second-largest automaker was thrown into question after Piech said he’s distanced himself from Winterkorn and no longer sees his long-time confidant as a candidate to succeed him as chairman.