Germany's transport minister has accused Fiat Chrysler of "uncooperative behavior" after the Italian-American automaker failed to show up for a meeting to discuss the emission levels of its diesel vehicles.

Alexander Dobrindt said in a statement Thursday that Fiat's behavior was "completely incomprehensible" as there were "concrete allegations" against the automaker.

Dobrindt had asked Fiat representatives to meet with officials Thursday as part of a broader probe into illegal diesel emissions controls sparked by the Volkswagen scandal. The German carmaker has admitted using software to cheat on U.S. emissions.

The transport ministry said it received a letter from Fiat's lawyer canceling the meeting on the grounds that the company's cars are certified by Italian authorities, meaning that country is responsible for any investigation.