United States President Donald Trump said on 2 December that he would impose tariffs on steel and aluminum from Brazil and Argentina, after accusing them of weakening their currencies and hurting American farmers.

“Brazil and Argentina have been presiding over a massive devaluation of their currencies. which is not good for our farmers. Therefore, effective immediately, I will restore the Tariffs on all Steel & Aluminum that is shipped into the U.S. from those countries,” Trump tweeted.

Both countries, after they agreed to quotas, were exempted from steel and aluminum tariffs last year, when Trump was attempting to avoid a trade war with them.

Brazil’s government said it was already in discussions with Washington, while Argentina’s production minister, called Trump’s announcement “unexpected” and said he would seek talks with US officials.

Trump also urged the US central bank to prevent other countries from devaluing their currencies, explaining that devaluation makes it very hard for US manufacturers and farmers “to fairly export their goods.”