Larry Kudlow, Director of the United States National Economic Council, speaks to reporters in the White House Press Briefing room. "He really, actually, you know what, he did a great disservice to the whole G-7".
Other Trump advisers also attacked Trudeau in appearances on Sunday.
The remarks apparently upset Trump, who had left the conference early to travel to Singapore for a highly anticipated meeting with North Korean leader Kim Jong-un.
Trump - who has a history of hair-trigger responses to slights - landed in Singapore on Sunday for the Tuesday summit meeting with Kim.
"I have made it very clear to the President that it is not something we relish doing, but it is something that we absolutely will do". In a series of tweets, the U.S. president called him "very dishonest and weak" and accused him of making false statements.
'As Canadians, we are polite, we're reasonable, but also we will not be pushed around, ' he said.
The president concluded his tweetstorm by saying, "Sorry, we can not let our friends, or enemies, take advantage of us on Trade anymore".
Trump announced on Twitter he had made the decision following comments from Trudeau that Canada would move ahead with imposing retaliatory measures on the USA in response to newly imposed tariffs imposed by the U.S. on aluminum and steel. "He is a thug using Soviet-style aggression to wage a shadow war against America, and our leaders should act like it", Sasse said.
"He didn't attack [President Trump] in any way, other than restate Canada would retaliate for tariffs".
Trump called Trudeau "very dishonest and weak" on Twitter on Saturday and then sent Kudlow and trade adviser Peter Navarro to hammer the message home on Sunday morning news shows in an extraordinary assault on a close US ally and neighbor.
"That's what matters", he wrote.
French President Emmanuel Macron's office reacted Sunday by saying that "international cooperation can not be dictated by fits of anger and throwaway remarks". We are sticking to them and whoever reneges on them is showing incoherence and inconsistency. Canadians, he said, "will not be pushed around".
June 9 - Trump extols his relationship with Trudeau and Canada as a 10 out of 10, blasting reports of a rift as "fake news".
On board Air Force One, an AFP reporter was told that Trump had approved the agreement, only to be told later of the tweets.
Mr Trump went on to lambast fellow members of North Atlantic Treaty Organisation for paying disproportionately less than the U.S. to maintain the Western alliance.
Europe's answer must be to stick even closer together, defend its interests and strengthen alliances with countries such as Japan and Canada, Mr Maas said. "Back to embarrassment-we, frankly, ought to feel a little bit ashamed for treating such a good friend the they they were treated yesterday from very high levels in our government".
"We strive to reduce tariff barriers, non-tariff barriers and subsidies", it said.
Merkel, whose office over the weekend released a photo of leaders and aides which illustrates the divide between Trump and his allies, said she had "tried hard to find a compromise and we fought hard for it. this was an important announcement".