US President Donald Trump has said he will place tariffs on steel and aluminium imports from Brazil and Argentina.
He justified the move saying those countries' weak currencies had made it harder for US food exports to compete.
"Brazil and Argentina have been presiding over a massive devaluation of their currencies, which is not good for our farmers," Mr Trump said.
Brazil's President Jair Bolsonaro said he would seek talks with Mr Trump.
"Their economy is not comparable with ours, it's many times bigger. I don't see this as retaliation," Mr Bolsonaro said in a radio interview with Brazil's Radio Itatiaia.
"I'm going to call him so that he doesn't penalise us. Our economy basically comes from commodities, it's what we've got," he said.