Canada and Mexico have already criticized the threats and are not changing their stance in the face of US ultimatums on contentious issues, such as rules of origin. The 3 countries are renegotiating the decades-old NAFTA trade deal. Officials said those exemptions would be made on a "case by case" and "country by country" basis.
The president has said the tariffs are needed to reinforce lagging American steel and aluminium industries and protect national security. It's not like American producers will keep prices where they are and simply manufacture more steel to make up for the lost imports.
He says the tariffs are necessary for national security, noting the materials are used for building fighter jets and navy ships.
The exemptions for USA trading partners in North America are part of a broader negotiating strategy from Trump's administration.
But the industry also fears the indirect consequences of Mr Trump's actions, which could lead to cheap Chinese steel being dumped on European markets instead of sold to the USA.
Some, including the European Union, have threatened retaliatory tariffs on United States products such as bourbon whiskey and Harley-Davidson motorcycles. "When you add intellectual property, it's much higher than that", Trump said.
The head of the United Nations trade and development agency Unctad said the tariffs would take a toll on poorer countries and could trigger takeovers in their mining industries.
An exemption from Donald Trump's tariffs on Australian steel will still mean trouble for local companies with operations in other countries, an industry group warns.
Thousands of eggs, embryos possibly damaged at OH hospital
An American Society for Reproductive Medicine rep says nothing like this has ever happened at a United States fertility clinic. Storage for embryos also cost hundreds of dollars from year to year but have shown to last in the freezer process for decades.
In the event of a breakdown over NAFTA, these tariffs would likely bring swift retaliatory tariffs on USA goods imported into Canada.
Nations can apply for exemptions, something Australian Foreign Affairs Minister Julie Bishop - who is in the U.S. this week, said Australia will do.
He said the move was aimed at protecting U.S. jobs.
"We're going to be very fair, we're going to be very flexible but we're going to protect the American worker as I said I would do in my campaign", Trump said. The US would offer temporary tariff relief to Canada and Mexico for 30 days, the Washington Post reported citing senior officials, breaks that could be extended depending on progress in the ongoing North American FTA negotiations.
The U.S.is answering the "assault on our country", he said.
Making the long-awaited announcement on Thursday, the president said the industry had been "ravaged by aggressive foreign trade practices".
"The short answer is, we don't know the specifics yet", said Orr, who was assistant USA trade representative in President George H.W. Bush's administration.