The United States on Thursday said it was moving ahead with tariffs on aluminum and steel imports from Canada, Mexico and the European Union, ending a two-month exemption and potentially setting the stage for a trade war with some of America's top allies.

U.S Commerce Secretary Wilbur Ross told reporters on a telephone briefing that a 25 percent tariff on steel imports and a 10 percent tariff on aluminum imports from the EU, Canada and Mexico would go into effect at midnight (0400 GMT on Friday).

"We look forward to continued negotiations, both with Canada and Mexico on the one hand, and with the European Commission on the other hand, because there are other issues that we also need to get resolved," he said.

On NAFTA, Ross said there was "no longer a very precise date when they may be concluded and therefore (Canada and Mexico) were added into the list of those who will bear tariffs."

Ross offered little detail about what the EU, Canada and Mexico could do to have the tariffs lifted.

He said he planned to travel to China on Friday for trade talks between the world's two biggest economies.

Financial markets dipped amid concerns about the disputes among trading partners, with the Dow Jones industrial average dropped more than 200 points.

The U.S. first announced the tariffs in March, giving reprieve key allies while terms could be negotiated. Dissatisfied with the negotiations, Trump lifted the exemptions, in a move likely to provoke counteraction from trade allies.

French Finance Minister Bruno Le Maire warned enacting steel and aluminum tariffs would trigger swift retaliation.

"The responsibility falls solely on to US authorities. Only they have to decide whether they want to enter a trade war with their closest partners," Le Maire said, adding that Trump had given "the wrong response" to "an urgent need to reform global trade."

Jean-Baptiste Lemoyne, junior minister of foreign affairs, told journalists in Paris Thursday: "France disapproves of these unjustified and unjustifiable measures."

The EU trade commissioner, Cecilia Malmstrom, said Thursday the EU "did everything to avoid this outcome," as the bloc announced it would bring the case to the World Trade Organization (WTO) on Friday.

The EU also vowed to retaliate against a list of U.S. goods worth over $3 billion, including bourbon, orange juice, motorcycles and blue jeans.

Canada announced retaliatory duties on American goods worth up to Can$16.6 billion (USD$12.8 billion) as Prime Minister Justin Trudeau called U.S. tariffs "totally unacceptable."

"These tariffs are an affront to the long-standing security partnership between Canada and the United States, and in particular, an affront to the thousands of Canadians who have fought and died alongside their American brothers in arms," he said, noting the U.S. national security justification for its measures.

The Canadian tariffs, which Foreign Minister Chrystia Freeland said are proportional to the U.S. duties, will be applied to US steel and aluminum as well as consumer products.

Ottawa will also challenge the U.S. measures under NAFTA and at the WTO, said Trudeau.

Mexico also promised a tit-for-tat reaction, saying it would take "equivalent measures" against U.S. products.

The Mexican economy ministry announced equivalent tariffs on goods ranging from steel to lamps to apples, "up to an amount matching the level of impact" from the US tariffs.

"Mexico deeply deplores and condemns the decision by the United States to impose these tariffs," it said in a statement.

"Mexico has stated repeatedly that this type of measure, based on national security, is neither appropriate nor justified."

Ross downplayed the threat of a trade war, calling the changes mere "blips on the radar" in an interview with broadcaster CNBC.

"I don't think they change the fundamentals of the relationship. Everybody has spats every now and again … I think everybody will get over this in due course," he said.

New York stocks extended opening losses after Ross announced the tariffs.

European key markets also fell, having earlier been on the path to recovery as investors took a more sanguine view of an ongoing political crisis in Italy.

The euro reversed earlier gains as inflation in the eurozone rose to the ECB's target in May, fueled by a huge increase in oil prices as the U.S. decided to pull out of a nuclear deal with Iran.

Asian equities bounced back from Wednesday's mauling as fears of turmoil in Italy were soothed by conciliatory noises from the country's two biggest populist parties.

In Frankfurt, shares in Deutsche Bank fell sharply, losing seven percent at the close, after the U.S. Federal Deposit Insurance Commission classified the German lender among its "problem banks" according to a person familiar with the matter.

The designation adds to the woes facing the big German bank, which also was downgraded to "troubled condition" by the Federal Reserve, the Wall Street Journal reported.