In the two tweets that ended US support for the joint G-7 statement, Trump accused Trudeau of having made "false statements" during a news conference.
"PM Justin Trudeau of Canada acted so meek and mild during our G7 meetings only to give a news conference after I left saying that, "US Tariffs were kind of insulting" and he "will not be pushed around".
President Donald Trump attacked America's closest allies in tweets after leaving the meeting in Canada.
President Donald Trump said Saturday that North Korean leader Kim Jong Un has a "one-time shot" to show he's serious about a nuclear disarmament deal. One of its early tweets read: numerous jokes were directed at the XX-year-old Canadian President, who bore the brunt of a twitter attack from President Trump and his White House advisers.
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. "And that's what bad-faith Justin Trudeau did with that stunt press conference", White House trade adviser Peter Navarro said during a Fox News interview Sunday.
"So long as the USA government persists on its present course where the instinct is to undo anything that is already there", said Sebastian Mallaby, senior fellow at the Council on Foreign Relations, in a phone call with reporters ahead of the weekend summit.
While the agreement of legislators who are normally opposed on most fronts was remarkable, the anger also spread to pundits, officials, celebrities and ordinary citizens as Canadians vowed consumer boycotts of American goods and brainstormed insults of Trump on social media. And chief economic adviser Larry Kudlow accused Trudeau of betrayal and stabbing Trump in the back.
The president recently imposed sweeping tariffs on steel and aluminum imports, fulfilling a campaign promise.
European Commission President Jean-Claude Juncker is set to debrief Commissioners about the G7 and underline the commitment made by the EU in the communiqué to "continue to stand up for an worldwide rules-based multilateral system". United States officioals too, took on Mr Trudeau. Trump said in a second tweet.
So Trump's national security justification is so laughable that Republicans who have been willing to stick by Trump through every other blunder are ready to work with Democrats to block these tariffs by holding military spending hostage.
Trudeau used a media conference on Saturday to reject a United States demand for a sunset clause in the North American trade agreement, Nafta, that Trump has at different times pressed to abolish or renegotiate.
While trade is expected to dominate, Trudeau also wants to focus on gender equality and climate change.
But Trump had already said he would not hesitate to shut countries out of the USA market if they retaliate against his tariffs.