US tariffs on European metals would be unjustified and dangerous for growth and free trade, French Finance Minister Bruno Le Maire told US Commerce Secretary Wilbur Ross on Thursday, hours ahead of Washington's decision on the matter.

"It's entirely up to US authorities whether they want to enter into a trade conflict with their biggest partner, Europe," Le Maire told reporters after meeting Ross in Paris.

Le Maire repeated that the EU would take "all necessary measures" to respond if the United States decided to impose tariffs.