White House trade adviser Peter Navarro has apologised for his sharp comments directed at Canadian Prime Minister Justin Trudeau after last week’s G7 summit.
At an event hosted by the Wall Street Journal, Mr Navarro said he had made a mistake.
“My mission was to send a strong signal of strength,” Mr Navarro said at the event.
“The problem is that in conveying that message I used language that was inappropriate.”
The admission was a rare act of contrition from US President Donald Trump’s White House, where public apologies are few.
Canada reacted coolly to the apology, with Mr Trudeau declining to answer when reporters asked him whether he accepted it.
“We will continue to conduct our diplomacy the Canadian way, that is, being positive and constructive and firm in defending the interests of our industries … in diplomacy it doesn’t really matter about personal feelings and personal comments,” Trade Minister Francois-Philippe Champagne said when asked about the apology.
Mr Navarro condemned Mr Trudeau following the Canadian leader’s news conference after his summit meeting with Mr Trump and other G7 leaders.
“There is a special place in hell for any 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 and that’s what bad-faith Justin Trudeau did with that stunt press conference,” Mr Navarro said on the Fox News Sunday program.
“That’s what weak, dishonest Justin Trudeau did.”
A day before, White House economic adviser Larry Kudlow also lashed out at Mr Trudeau.
Both aides accused Mr Trudeau of betraying Mr Trump when he gave a news conference after the US president had departed.
At the event, Mr Trudeau said Canada would take retaliatory steps in response to Mr Trump’s steel and aluminium tariffs imposed on Canada and other allies.