Peter Navarro, one of President Donald Trump’s top trade advisers, apologized Tuesday for saying over the weekend that there was “a special place in hell” for Canadian Prime Minister Justin Trudeau.

Navarro said at a Wall Street Journal event that the heated comments he made Sunday were “inappropriate” and a “mistake,” according to several news outlets.

“I used language that was inappropriate, and basically lost the power of that message,” Navarro said. “That was my mistake, those were my words.”

Navarro came under scrutiny Sunday for bashing Trudeau after the prime minister criticized Trump in the wake of the G-7 summit held in Canada.

“There’s a special place in hell for any foreign leader that engages in bad-faith diplomacy with President Donald J. Trump and then tries to stab him in the back on the way out the door,” Navarro said during an appearance on “Fox News Sunday.”

“And that’s what bad faith Justin Trudeau did with that stunt press conference,” he said. “That’s what weak, dishonest Justin Trudeau did, and that comes right from Air Force One.”

Navarro’s comments came the day after Trudeau vowed not to be “pushed around” by the U.S. in response to Trump’s decision to impose stiff tariffs on Canada.

“Canadians … stood shoulder-to-shoulder with American soldiers in far-off lands in conflicts from the First World War onward,” Trudeau said Saturday at a press conference, The Washington Post reported. “It’s kind of insulting. … Canadians, we’re polite, we’re reasonable, but we also will not be pushed around.”

Trump quickly fired back on Twitter, calling Trudeau’s comments “very dishonest and weak.” He continued to bash the Canadian leader Tuesday during an interview with ABC News’ George Stephanopoulos.

“I actually like Justin, you know, I think he’s good, I like him, but he shouldn’t have done that,” Trump said. “That was a mistake. That’s going to cost him a lot of money.”