BERLIN (Reuters) - Audi's NSUG.DE 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.

Audi A8 models are seen at their plant in Neckarsulm near Heilbronn May 21, 2015. Audi will hold their annual shareholders meeting on May 22, 2015. REUTERS/Michael Dalder

The German Transport Ministry said it has asked Volkswagen's VOWG_p.DE luxury division to recall around 24,000 A7 and A8 models built between 2009 and 2013, about half of which were sold in Germany.

VW Chief Executive Matthias Mueller was summoned to the Berlin-based ministry on Thursday, a ministry spokesman said, without elaborating. VW didn’t return calls seeking comment.

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.

It is also the first time that Audi’s top-of-the-line A8 saloon has been implicated in emissions cheating. VW has said to date that the emissions-control software found in its rigged EA 189 diesel engine does not violate European law.

The 80,000 3.0-liter vehicles affected by VW’s emissions cheating scandal in the United States included Audi A6, A7 and Q7 models as well as Porsche and VW brand cars.

The ministry said it has issued a June 12 deadline for Audi to come up with a comprehensive plan to refit the cars.

Ingolstadt-based 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.

When Audi’s headquarters were raided by prosecutors on March 15 in connection with the emissions fraud, Chief Executive Rupert Stadler said investigations into the scandal were far from over, promising to keep at it until the work was done.

A source close to Audi said problems in the interaction between transmission and engine control units are to blame for the emissions overshoot. A proposal for a fix has already been submitted to the KBA, the source said, declining to elaborate.