German car giants Volkswagen and Daimler said Monday they are under investigation by EU antitrust regulators, in a new blow to the country's beleaguered auto industry.

Mercedes-Benz maker Daimler said the officers were carrying out an "inspection" at its offices and that it has "filed a leniency application". 

Separately, Volkswagen said it was also a target of "ongoing antitrust investigations by the EU commission".