German Transport Minister Andreas Scheuer has threatened to fine Daimler $4.4 billion (3.75 billion euros) for diesel-powered vehicles that have been fitted with emissions cheating software.

Local magazine Spiegel reports that Scheuer questioned Daimler boss Dieter Zetsche on Monday about Mercedes-Benz vans and car models recently found to feature illegal software.

Scheuer reportedly said that up to 750,000 vehicles from Mercedes could be affected and that the government might impose fines of up to 5,000 euros ($,5834) per vehicle, Reuters notes.

In an email, a transport ministry spokesman said Daimler and the ministry would clear up complex technical issues involved with diesel emissions.

Daimler is in hot water

As recently reported, German motor vehicle authority KBA ordered Daimler to recall Vito vans fitted with a 1.6-liter diesel engine from Renault. The automaker claims that it will appeal KBA’s decision and contest its findings of the software being illegal in court if needed.

Spiegel suggests that diesel engines used by the Mercedes-Benz C-Class also breach emissions rules.

Daimler representatives are expected to be summonded to the ministry before a second meeting between Zetsche and Scheuer towards the end of this month.

Germany has imposed particularly strict regulations after Volkswagen’s dieselgate scandal of 2015 and certain cities can now ban older diesel vehicles.