The European Union has vowed to take firm and proportionate countermeasures in response to U.S. President Donald Trump’s imposition of tariffs on all steel and aluminum imports.

European leaders said they would respond firmly to higher levies on steel and aluminum, but they had yet to say what that retaliation would look like.

The European Union said it would respond with "firm and proportionate countermeasures" after U.S. President Donald Trump's decision to impose tariffs on all steel and aluminium imports, escalating fears of a trade war.

The European Union's executive branch has vowed to "take firm and immediate action" against U.S. President Donald Trump's imposition of tariffs on steel and aluminum.

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.

Trump signed proclamations raising the U.S. tariff rate on aluminum to 25% from his previous 10% rate and eliminating country exceptions and quota deals. The measures will take effect on March 4.

European Commission President Ursula von der Leyen said the bloc will respond if Donald Trump follows through on his threat to impose global reciprocal tariffs, calling them a “step in the wrong direction.

The economic chill from U.S. President Donald Trump’s threat of tariffs is being felt worldwide. U.S. President Donald Trump has repeatedly characterized the European Union (EU) as a bad trading partner.

The European Union hopes to avert a damaging trade war with the U.S. over impending metals tariffs by prioritising negotiations rather than retaliatory countermeasures, EU officials signalled on Wednesday.