BRUSSELS (AP) — The European Union says that its reaction will be "swift and adequate" if U.S. authorities conclude that European cars are a threat to national security and should be hit with punitive tariffs.

The U.S. Commerce Department is expected to issue soon an opinion on whether auto imports endanger U.S. national security enough to justify import taxes. U.S. President Donald Trump would then have 90 days to decide whether to impose them.

EU spokesman Margaritis Schinas said Monday that if the U.S. goes ahead with "actions detrimental to European exports, the European Commission would react in a swift and adequate manner."

The EU and the U.S. have been trying to work out a trade deal but progress has been slow.