WASHINGTON — Peter Navarro, one of President Trump’s top trade advisers, said on Tuesday that it was a mistake to suggest that “there is a special place in hell” for Prime Minister Justin Trudeau of Canada, offering a rare apology from a White House that almost never walks back heated rhetoric.

“In conveying that message, I used language that was inappropriate and basically lost the power of that message,” Mr. Navarro said at an event hosted by The Wall Street Journal. “I own that, that was my mistake, those were my words.”

He said he was trying to send a signal of strength on behalf of the administration, but that his language was inappropriate. In the future, Mr. Navarro said, he will stick to discussing serious policy issues and differences.

“If you make a mistake, you should admit it, learn from it, don’t repeat it,” Mr. Navarro said.

Asked if he was apologizing, Mr. Navarro said, “yeah, absolutely.”