Ready to respond
Canada and Mexico have said they are prepared if Trump goes through with his plan.
Canadian Prime Minister Justin Trudeau said Friday that Ottawa is ready with "a purposeful, forceful" response.
Doug Ford, premier of Canada's economic engine Ontario, warned Saturday that "the impact of these tariffs will be felt almost immediately," predicting job losses and a slowdown in business.
Canada should "hit back hard and hit back strong," he said at a local election campaign stop.
Mexican President Claudia Sheinbaum previously said her government would await any announcement "with a cool head" and had plans for whatever Washington decides.
White House Press Secretary Karoline Leavitt, however, on Friday dismissed concerns of a trade war.
Hiking import taxes on crude oil from countries like Canada and Mexico could bring "huge implications for US energy prices, especially in the US Midwest," noted David Goldwyn and Joseph Webster of the Atlantic Council.
Trump said Friday he was mulling a lower tariff rate on oil.
He told reporters: "I'm probably going to reduce the tariff a little bit on that."
"We think we're going to bring it down to 10 percent," he added.
Nearly 60 percent of US crude oil imports are from Canada, according to a Congressional Research Service report.
Canadian heavy oil is refined in the United States and regions dependent on it may lack a ready substitute.
Canadian producers would bear some impact of tariffs, but US refiners would also be hit with higher costs, said Tom Kloza of the Oil Price Information Service.
(Source: Aurelia END with Beiyi SEOW in Washington, Agence France-Presse)