At the height of the Volkswagen emissions scandal, Audi has announced that 2.1 million of its cars sold in Europe, U.S.A. and Canada were equipped with the controversial defeat device, a software program designed to lower the vehicle's actual emissions when it is being tested. Audi has stated on Monday that several models were affected, including the A1, A3, A4, A5, A6, TT, Q3 and Q5 models, according to The Wall Street Journal.

Audi spokesman Jürgen De Graeve has stated that none of the rigged cars have been sold in China or Japan. Of the 2.1 million vehicles that were equipped with the illegal device, more than 2 million of them were sold in Europe, while about 13,000 were sold in the U.S. and Canada.

The announcement from Audi came as German prosecutors initiated an investigation against the company's former CEO, Martin Winterkorn, focusing on allegations of fraud in the sale of cars with manipulated emissions data, reports The Independent.

The scandal has stained the reputation of Volkswagen, one of the world's most respected car companies. Due to the allegations, the company now faces as much as 18 billion dollars in U.S. fines, while its shares fell almost 30 percent last week.

In light of the scandal, Winterkorn quit his post as CEO of the company, being replaced by Matthias Mueller, the former chairman of Porsche. Despite the change of leadership, Volkswagen's shares continued to drop on Monday, falling nearly another seven percent.