Audi says 2.1m of its cars are affected, as Volkswagen is said to have suspended the R&D heads of three divisions.
Audi says 2.1m of its cars were fitted with emission cheating software, as Volkswagen is said to have suspended the research and development heads of three divisions.
The luxury car brand, which is a subsidiary of Volkswagen, has admitted that millions of its vehicles with so-called EU5 engines have an emissions "cheat device" installed.
The news comes as reports suggest the R&D chief of Audi, along with those of Volkswagen's core passenger car division and sports car maker Porsche, is reported to have been put on leave.
All three companies have declined to comment.
Volkswagen was forced to apologise last week after it was discovered that it had developed the device in order to trick emission tests in the US.
The devices are able to detect when cars are undergoing tests, and can switch the vehicle to a low emission mode in order to achieve more favourable results.
This means that many people have bought cars which are much less environmentally friendly than they had been led to believe.
According to the Audi spokesman, around 1.42 million Audi vehicles in Western Europe are fitted with the device, with 577,000 in Germany.
Another 13,000 Audi cars in the US are affected.
Vehicle lines involved include the Audi A1, A3, A4, A5, A6 and the TT, Q3 and Q5 models.
Volkswagen said last week that around 11 million of its cars worldwide have been fitted with the cheat device.
Then CEO of the Volkswagen Group, Martin Winterkorn, has been forced to resign over the revelations and was replaced by Matthias Müller, who has been the chief of another Volkswagen subsidiary, Porsche, since 2010.