Canadian Prime Minister Justin Trudeau speaks during a joint press conference with US President Donald Trump in the East Room of the White House in Washington, DC, February 13, 2017.

Canadian Prime Minister Justin Trudeau on Thursday repeated his opposition to a U.S. proposal for an import tax, telling energy executives gathered in Houston a levy would hurt both economies.

"Anything that creates impediments at the border, extra tariffs, new taxes is something we're concerned with," Trudeau said, adding: "You're going to be hurting not just the Canadian economy but the American economy as well."