Trudeau had said using national security as a justification for tariffs was "kind of insulting" to Canadian veterans who had stood by their United States allies in conflicts dating back to World War I.
Trump fired off a volley of tweets on Monday further venting anger at North Atlantic Treaty Organisation allies, the European Union and Trudeau.
Republican senators sharply criticized Navarro on Monday.
Navarro's original statement, on "Fox News Sunday", followed a pair of tweets in which Trump raged about comments Trudeau made at a news conference after a summit of the Group of Seven industrialized nations. He also said the USA had a trade deficit of $17 billion with Canada, though he implied that it might be as large as $100 billion.
"It's very unfair to our farmers, and it's very unfair to the people of our country", Trump said Tuesday in Singapore. At one point he wrote, "Justin acts hurt when called out!"
Yet his top diplomat, Secretary of State Mike Pompeo, downplayed the severity of the rift.
"There are always irritants in relationships", Pompeo said, adding that without partners like Canada, "we wouldn't be in this place, we wouldn't have this diplomatic opportunity" with the North. "And that comes right from Air Force One". He had other things, bigger things, on his plate in Singapore. "Canadian relations to have this kind of rhetoric out there", said Klein, who will soon turn 80. "That will not stand".
The president's staff then blasted Trudeau on Sunday with economic advisor Larry Kudlow accusing Canada of stabbing the U.S.in the back.
The Canadian prime minister has been under attack from various members of the Trump administration since his remarks at the G7.
Canada's prime minister earned Trump's ire by giving a press conference, after the U.S. president left La Malbaie, in which he spoke critically of United States trade policy and said Canada would "move forward with retaliatory measures" in response to Trump's move to impose tariffs on aluminum and steel.
The Canadian Prime Minister initially said Trump's claims that Canadian steel posed a national security threat were dishonest. Can't do it in person.
"On (Trump's) comments, I'm going to stay focused on defending jobs for Canadians and supporting Canadian interests".
"Obviously we support the continuing efforts by the President on North Korea", the Canadian prime minister said. "I've had a good relationship with Justin". From promoting democracy and to fighting terrorism, "we're on the same page".
"So you know, it is something that we have discussed, and Canada is certainly prepared for any eventuality", said Freeland.