Trump threatens 20% tariffs on European autos

"Based on the Tariffs and Trade Barriers long placed on the U.S. and it great companies and workers by the European Union, if these Tariffs and Barriers are not soon broken down and removed, we will be placing a 20% Tariff on all of their cars coming into the U.S." he wrote on Twitter.

"Build them here!" he declared.

Last month Trump instructed his Commerce Department to begin a national security investigation that would provide the legal underpinning of new tariffs on cars.

He has raged in public and private against trade imbalance, particularly with Germany, as it relates to auto imports.

"You look at the European Union -- they put up barriers so that we can't sell our Ford products in, and yet they sell Mercedes and BMW, and the cars come in by the millions, and we hardly tax them at all. They don't take our cars. And, if they do, the tax is massive," he said during a campaign rally in Duluth on Wednesday.

"So, they're basically saying, 'We are going to sell you millions of cars. By the way, you're not going to sell us any.' Not going to work that way anymore, folks. Not going to work that way," he continued.