The European Union is broadening the list of US goods it will target with retaliatory tariffs if US President Donald Trump follows through on his threat to impose duties on steel and aluminum exports,

Commission President Ursula von der Leyen said unjustified tariffs would prompt "proportionate and decisive countermeasures", echoing her vow on Tuesday of a "firm and proportionate" response to Trump's decision to impose tariffs on all steel and aluminum imports.

The European Union's top trade officials said on Wednesday the bloc was interested in making mutually beneficial trade deals with U.S. President Donald Trump, and was ready to discuss the potential for reducing or eliminating tariffs on motor vehicles and other goods.