BERLIN -- Audi's emissions scandal flared up again on Thursday after the German government accused the carmaker of cheating emissions tests with its top-end models, the first time Audi has been accused of such wrongdoing in its home country.
The German Transport Ministry said it has asked Volkswagen Group's luxury division to recall A8 and A7 models built between 2009 and 2013.
VW Group CEO Matthias Mueller was summoned to the Berlin-based ministry on Thursday, a ministry spokesman said, without elaborating.
The affected Audi models with so-called Euro-5 emission standards emit about twice the legal limit of nitrogen oxides when the steering wheel is turned more than 15 degrees, the ministry said.
The ministry said it has issued a June 12 deadline for Audi to come up with a comprehensive plan to refit the cars.
Audi issued a recall for the 24,000 affected models late on Thursday, some 14,000 of which are registered in Germany, and said software updates will start in July. It will continue to cooperate with Germany's KBA motor vehicle authority, Audi said.
"Engine speed can be influenced unfavorably by the gearbox software" in the affected cars, Audi said. They can be made compliant with a software update that takes about 30 minutes, the automaker said.
The latest revelation comes two weeks after Audi prolonged the contract of CEO Rupert Stadler.
VW Group Chairman Hans Dieter Poetsch said last month that investigations by external law firms haven't brought any evidence that board members were aware of or involved in the illicit conduct.
Audi's headquarters in Ingolstadt, Germany, were raided by prosecutors on March 15 in connection with the emissions fraud. Munich prosecutors responded to Thursday's news by extending an existing Audi probe to include the additional models.
It's the first time that office is investigating Audi cars sold in Europe, as the review so far has been limited to U.S. sales. The 80,000 3.0-liter vehicles affected by VW Group's emissions cheating scandal in the United States included Audi A6, A7 and Q7 models as well as Porsche and VW brand cars.
Prosecutors said the suspicion in the Audi investigation still centered on fraud, adding it has not yet received updated information from the KBA.
The fresh findings on Audi's top models are a blow to a company that's VW's biggest profit contributor and therefore a vital component to absorb the hit from the diesel-emissions scandal that has cost the manufacturer 22.6 billion euros ($25.4 billion) so far. From the roughly 11 million diesel cars affected worldwide across the VW group, Audi has accounted for about 2.1 million vehicles until now.
Audi has been falling behind German rivals Mercedes-Benz and BMW in the global luxury-car race, and now ranks third in sales, having previously aspired to gain the top slot.
Bloomberg contributed to this report