Kudlow said the United States participated in G7 talks and bilateral talks on Nafta in good faith and that Trump had been "charming".
Tweeting from Singapore where he's scheduled to hold a nuclear summit with North Korean dictator Kim Jong Un, Trump wrote: "Sorry, we can not let our friends, or enemies, take advantage of us on trade anymore".
US President Donald Trump called Mr Trudeau "very dishonest and weak" after leaving the Group of Seven heads of government meeting in Canada on Sunday, shattering any hope its northern neighbour could avoid US tariffs on steel and aluminium, or renegotiate the North American Free Trade Agreement.
"In a matter of seconds, you can destroy trust with 280 Twitter characters", German Foreign Minister Heiko Maas said when asked about Mr Trump's U-turn, adding it would take much longer to rebuild lost trust.
"Canada will impose more tariffs; the trade war will get worse before it gets better", Valliere said.
Donald Trump's tirade against Canadian Prime Minister Justin Trudeau's statement after the G7 summit may not have been related to Ottawa's stance on United States tariffs on steel and aluminum, Canadian based media The Star reported.
Trump, who attended a G7 meeting in Quebec before heading to Singapore on Saturday, withdrew from a joint statement drafted by the global organization on trade.
The Prime Minister said the United Kingdom still wanted to discuss a post-Brexit trade deal with the USA and said Mr Trump was still looking forward to July's visit to Britain.
The verbal volleys by Navarro and Mr. Trump's top economic adviser, Larry Kudlow, picked up where Mr. Trump left off Saturday evening with a series of tweets from Air Force One en route to Singapore for his nuclear summit Tuesday with North Korea's Kim Jong Un.
Based on Justin's false statements at his news conference, and the fact that Canada is charging massive Tariffs to our U.S. farmers, workers and companies, I have instructed our U.S. Reps not to endorse the Communique as we look at Tariffs on automobiles flooding the U.S. Market! Still, numerous Canadian officials, including Trudeau's spokesperson, noted that he said nothing new or anything that hadn't been discussed with Trump in private.
"We would hope that the U.S. will similarly honour the commitments that they have made", he said, speaking before a parliamentary statement on the summit by Prime Minister Theresa May.
"Canadians, we're polite, we're reasonable, but we also will not be pushed around", Trudeau said. The Canadian leader pulled a "sophomoric political stunt for domestic consumption", Kudlow said, that amounted to "a betrayal". "But we say that with great sadness".
It also covered other issues including relations with Russian Federation. "But the conclusion I draw is that it is only through continued dialogue that we can find ways to work together to resolve the challenges we face".
Freeland, speaking at a press conference on Sunday, said that Canada does not believe that ad hominem attacks are a particularly appropriate or useful way to conduct relations with other countries. "But to walk away from our allies in this way, I think, is a mistake".
"One of the arguments was that the president can't show weakness and what Trudeau did required this robust response otherwise the president would appear to be weak", Hayden said.