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The EU has threatened "all necessary measures" in response
The US is to impose tariffs on metal and aluminium imports from the European Union, Mexico and Canada.
The 25% tariffs on metal and 10% on aluminium will start at midnight.
The transfer, revealed by Commerce Secretary Wilbur Ross, will have an effect on a number of key US alliesand Nato membersin Europe.
The UK was "deeply disappointed" by the US resolution, whereas Europe's commerce commissioner Cecilia Malmström known as it a "bad day for world trade".
Mr Ross introduced the sanctions from Paris, the place he had been negotiating with EU leaders who had been making an attempt to fend off the duties.
He stated talks had not made sufficient progress to warrant additional reprieve and acknowledged the potential for retaliation.
"We will have to see what's their reaction," he stated. "We continue to be quite willing and indeed eager to have discussions with all those parties."
French Finance Minister Bruno Le Maire had stated the tariffs could be "unjustified and dangerous".
The EU would take "all necessary measures" to reply if the US did impose tariffs, Mr Le Maire warned.
"It's entirely up to US authorities whether they want to enter into a trade conflict with their biggest partner, Europe," he stated earlier than the announcement was made.
Ben Digby, of UK enterprise foyer group the CBI, known as the tariffs "deeply concerning" however urged the events to be cautious, given the potential prices of a commerce struggle.
"Now is not the time for any disproportionate escalation, and we urge the EU to consider this when initiating its response," he stated.