Mulroney, who has a personal relationship with Trump and has been quietly advising the prime minister on how to deal with the mercurial US president, likened Trump's weekend tirade to "serious summer squalls".
"(Trudeau) really kind of stabbed us in the back", Kudlow, the director of the National Economic Council who had accompanied Trump to the summit of wealthy nations on Saturday, said on CNN's "State of the Union".
"On his comments, I'm going to stay focused on defending jobs for Canadians and supporting Canadian interests", Trudeau said before walking away from reporters.
While making no direct criticism of Mr Trump, Mrs May acknowledged that the summit had been "difficult" and told MPs she had expressed her "deep disappointment" at the "unjustified" imposition of tariffs on American imports of European steel and aluminium.
Trump was furious after Trudeau had said at the end of a contentious economic summit in Quebec that he wouldn't let Canada be pushed around in trade relations with the United States.
"We strive to reduce tariff barriers, non-tariff barriers and subsidies", the statement said, which came despite Washington appearing intent on taking more punitive steps on trade.
Trudeau had told reporters that Trump's decision to invoke national security to justify USA tariffs on steel and aluminum imports was "kind of insulting" to Canadian veterans who had stood by their USA allies in conflicts dating back to World War I.
"This was a hard summit, with at times some very candid discussions", Mrs May told MPs.
'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. "$800 billion trade deficit", he said.
The move also adds a new complication to efforts to renegotiate the trillion-dollar North American Free Trade Agreement (Nafta) between Canada, the United States and Mexico. The tariffs, which also take effect July 1, will last until the USA ends its trade action. Trump said it was snapped as they waited for changes he'd requested to the communique, which he ended up pulling out of. The French presidency had earlier condemned "fits of anger". A senior U.S. administration official said that Trump had been angered by Trudeau's comments.
The president recently imposed sweeping tariffs on steel and aluminum imports, fulfilling a campaign promise.
Trump advisers also took up the attack in appearances on Sunday's news shows, leveling more withering and unprecedented criticism against Trudeau, branding him a back-stabber unworthy of Trump's time.
The EU then announced retaliatory tariffs on U.S. goods ranging from Harley-Davidson motorcycles to bourbon. And experts say almost all unfair dumping on the metals market is done by China, not Canada, Mexico and Europe.