'Only losers' in US-EU trade war: French minister

French Economy Minister Bruno Le Maire on Friday warned the United States against a trade war with the EU, saying there would "only be losers" in such a standoff.

Le Maire said US President Donald Trump's plans to impose tariffs on steel and aluminium imports were "unacceptable" and would require a "strong, coordinated and united response from the EU" if implemented.

He said the tariffs would have a "major impact" on the European economy, citing producers with operations with France like the global steel giant ArcelorMittal and Vallourec, a world leader in industrial tubing, among those that would be affected.

In terms of response "all options are on the table", ranging from a challenge at the World Trade Organization to "counter-measures to limit US imports in Europe", he said.

Trump triggered a furore on Thursday by announcing he would set tariffs of 25 percent on steel and 10 percent on aluminium to protect US producers.

He did not specify if the tariffs would target specific countries, but his announcement caused an outcry among US allies such as Canada, the EU, Mexico and Australia as well as China, the world's biggest steel producer.

European Commission chief Jean-Claude Juncker vowed that the bloc "will react firmly" to defend its interests.

"We will not sit idly while our industry is hit with unfair measures that put thousands of European jobs at risk," he said Thursday.

EU Economic Affairs Commissioner Pierre Moscovici said Friday that the bloc was already preparing its response to the proposed tariffs. Trade wars "aren't good for anyone," he said in Paris.

"Nobody ever wins, these truly are pointless and unjustified wars, a lose-lose situation."

A defiant Trump reacted to mounting criticism by saying Friday that a trade war would be "good" for the US economy.

"When a country (US) is losing many billions of dollars on trade with virtually every country it does business with, trade wars are good, and easy to win," Trump tweeted.Le Maire took a swipe at China, which is accused by the United States and Europe of flooding their markets with low-cost imports.

"Some countries have (price) dumping practises and massive subsidies that distort world trade," he said, adding the subject "should be dealt with".