The scandal has sparked a US criminal investigation and worldwide legal action with unfathomable financial consequences for the auto giant.
"I am shocked by the events of the past few days. Above all, I am stunned that misconduct on such a scale was possible in the Volkswagen Group,"Winterkorn said in a statement issued by the carmaker.
According to the US authorities, VW has admitted that it equipped about 482,000 cars in the United States with sophisticated software that covertly turns off pollution controls when the car is being driven.
While France, Britain and other nations have called for a Europe-wide investigation, the United Nations has described the revelations as "extremely troubling."