The European Union will hit $39 billion worth of U.S. goods with tariffs if President Donald Trump goes through with his threat to impose duties on cars and auto parts from the European Union imported into the United States.

Bloomberg reports that European Trade Commissioner Cecilia Malmstrom revealed how the bloc would fire back at Trump earlier this week. She also said that the EU would reject any demand from the U.S. to limit its shipments of automotive products to the American market on the grounds that they pose a national security threat.

Also Read: Trump Rejects EU Offer For Zero Tariffs, Claims The Union Is Like China, Only Smaller

A figure of $22 billion had previously been spruiked by the EU in January but has been almost doubled to reflect the latest trade statistics.

“We will not accept any managed trade — quotas or voluntary export restraints — and if there were to be tariffs we would have a rebalancing list; it is already basically prepared worth 35 billion euros,” Malmstrom told a European Parliament committee in Brussels this week. “I would hope we do not have to use that one.”

The Trump administration has threatened to hit cars imported from the European Union with a 25 per cent levy. Estimates suggest this could add about $11,000 to the sticker price of each car imported into the U.S. from Europe. Such a tariff would follow on from the 25 per cent and 10 per cent levies on steel and aluminum introduced last year after Trump declared them to also be a national security threat.