Volkswagen export cars are seen in the port of Emden, beside the VW plant, Germany March 9, 2018. REUTERS/Fabian Bimmer

WOLFSBURG, Germany (Reuters) - Carmaker Volkswagen's VOWG_p.DE core autos division has queried why Europe levies an import tax on U.S. cars, after U.S. President Donald Trump threatened to tax cars from the European Union.

“You have to ask yourself why we in Europe demand a 10 percent tax on American cars. The Americans don’t do that,” Herbert Diess said on Wednesday at a news conference after the division reported results.

The United States is the second-biggest export destination for German auto manufacturers after China, while vehicles and car parts are Germany’s biggest source of export income.