Cecilia Malmstrom said: “Recently we have seen how [trade] is used as a weapon to threaten and intimidate us. But we are not afraid, we will stand up to the bullies.”

She made the statement after Donald Trump signed an order on Thursday last week imposing a 25% tariff on steel imports and 10% on aluminium.

Over the weekend, the bloc met with US trade representative Robert Lighthizer to resolve the tariff row, but did not come to an agreement.

Trump also confirmed last week his commerce secretary would be in contact with EU representatives about the matter. 

European leaders believe they should be exempt from the tariffs and have threatened retaliation if the plan goes ahead.

Trump insisted there would be a fair process of negotiation, including talks of exemptions. Canada and Mexico have already been exempt from the tariffs.

He said the tariffs would correct trading imbalances going back decades that had harmed the US job market and threatened US manufacturers.

The bloc believed it should be exempt as it is a close ally of the US.

But Trump said on Twitter on Saturday: “The European Union, wonderful countries who treat the US very badly on trade, are complaining about the tariffs on steel and aluminium.

"If they drop their horrific barriers & tariffs on US products going in, we will likewise drop ours. Big Deficit. If not, we Tax Cars etc. FAIR!."

The European Union, wonderful countries who treat the U.S. very badly on trade, are complaining about the tariffs on Steel & Aluminum. If they drop their horrific barriers & tariffs on U.S. products going in, we will likewise drop ours. Big Deficit. If not, we Tax Cars etc. FAIR!

— Donald J. Trump (@realDonaldTrump) March 10, 2018

German chancellor Angela Market also called for the EU to be exempted from the tariffs. She said: “The best option would be [for the EU] to be excluded.”

She warned that no one could win a “race to the bottom” and said the tariffs could risk “hurting everyone”.