ASG: U.S. president Donald Trump announced Monday that the United States will begin imposing Article 232 tariffs on steel and aluminum imports from Brazil and Argentina, which the White House has not officially announced as of Thursday.

Trump said in a tweet that the tariffs will take effect immediately. But if the president is to change established quotas or tariffs, he must issue a presidential announcement. But as of Thursday afternoon, the White House had taken no action. The White House did not respond to a request for comment.

The Trump administration imposed a 25 per cent tariff on all steel imports and a 10 per cent tariff on all aluminium imports under 232 pieces of legislation in March 2018, saying they posed a security risk to the US economy. In June 2018, restrictions on steel and aluminium in Brazil and Argentina were converted into quota systems.