A trade war is now a reality, French Finance Minister Bruno Le Maire has warned as G20 ministers gather for a summit in Argentina.
The current US trade policy of imposing unilateral tariffs is based on "the law of the jungle", he said.
But US Treasury Secretary Steven Mnuchin defended the tariffs and urged the EU and China to open their markets to allow free competition.
Last week, US President Donald Trump described the EU as a foe on trade.
Mr Trump later threatened to impose tariffs on all $500bn (£380bn) of Chinese goods entering the US in a growing trade row.
The US has large trade deficits with both the 28-member EU and China.
The two-day talks in Buenos Aires bring together finance ministers and central bankers of the world’s top 20 economies.
What did the French minister say?
“World trade cannot base itself on the law of the jungle and the unilateral increase of tariffs is the law of the jungle,” Mr Le Maire told AFP news agency.
“The law of the jungle, the law of the fittest, this cannot be the future of global trade relations.
“The law of the jungle will only turn out losers, it will weaken growth, threaten the most fragile countries and have disastrous political consequences,” Mr. Le Maire said.
He added that a trade war was now a reality, and that the EU could not consider negotiating a free trade deal with the US without America first withdrawing its tariffs on steel and aluminum.
Source: BBC