Winterkorn canceled his participation in the gathering of officials of the ruling Christian Democrats and Social Democrats due to take place near the town of Goettingen, Germany because of meetings at the Wolfsburg-based carmaker, Thomas Oppermann, the Social Democrats' parliamentary leader said.

VW confirmed the cancellation of Winterkorn's planned attendance.

A source familiar with the matter earlier told Reuters that VW's supervisory board steering committee was to meet on Thursday to try to resolve a leadership crisis caused by the exposure of a rift between Winterkorn and Chairman Ferdinand Piech.

(Reporting by Andreas Rinke; Writing by Andreas Cremer; Editing by Maria Sheahan)