US president Donald Trump has pushed back his latest deadline for the imposition of wide-ranging new tariffs until the start of August, but the administration has begun sending letters to several key trading partners setting out proposed new levy rates.
Among those facing higher tariffs is Canada, which has been hit with a blanket rate of 35 percent separate from any tariffs levied on specific sectors. Brazil has also become a target for President Trump, with the South American nation facing a rate of 50 percent.
Both nations have been warned that they will face additional levies if they impose their own retaliatory tariffs on US goods.
In his letter to Canada, posted on his own Truth Social network, Mr Trump cited an alleged failure to tackle smuggling of fentanyl into the US as a reason for the tariffs.
This justification has been dismissed by Canadian prime minister Mark Carney, who wrote on social media: "Canada has made vital progress to stop the scourge of fentanyl in North America. We are committed to continuing to work with the United States to save lives and protect communities in both our countries."
Meanwhile, the tariffs on Brazil are in response to Mr Trump's unhappiness with the country's criminal case against former president Jair Bolsonaro, a close ally of Mr Trump who is currently on trial for allegedly attempting a coup to retake power following an election defeat in 2022.
Brazilian president Luiz Inácio Lula da Silva also rejected the rationale behind the tariffs, stating that his country's independent institutions "will not accept any tutelage" from the US. He added that any new tariffs would be met with reciprocal duties, despite the US threats.
Elsewhere, 21 other nations have also received tariff letters from the US this week, including Japan, South Africa, Thailand, Bangladesh, the Philippines and South Korea. The EU is also said to be expecting a similar missive in the coming days.