Just minutes after a joint statement that had been approved by G7 negotiators was published, Trump, who had left the meeting early to head for a nuclear summit with North Korea's Kim Jong-un, launched a Twitter broadside from aboard Air Force One.
Trump pulled his signature from the statement after hearing that Trudeau had told a news conference that the US president invoking security to justify tariffs against Canada was "kind of insulting".
"Canadians are polite and reasonable but we will also not be pushed around," he said.
Trump hit back with two furious tweets.
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.” Very dishonest & weak. Our Tariffs are in response to his of 270% on dairy!Donald J. Trump (@realDonaldTrump) 9 juin 2018
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!Donald J. Trump (@realDonaldTrump) 9 juin 2018
Trudeau's office issued a brief response, saying that the prime minister had "said nothing he hasn't said before, both in public, and in private conversations with the president".
A statement from the French presidency on Sunday declared that "international cooperation cannot depend on fits of anger and a few words".
"We spent two days producing a statement and commitments," it said. "We stand by it and whover leaves it and turns their back on it is showing insconsistency and lack of character."
Putin dismisses "babbling"
France will host next year's summit in the Atlantic resort of Biarritz and, following Trump's call for Russia to be brought back into the group, Macron said he would welcome its presence but on condition that it "makes a gesture" on Ukraine, where pro-Russian forces are in conflict with Kiev.
The G7 statement called on Russia to "cease its destabilising behaviour, to undermine democratic systems and its support of the Syrian regime” and said sanctions against Moscow could be stepped up if they were judged necessary.
Russian President Vladimir Putin, who is attending a meeting of the Shanghai Cooperation Organisation (SCO) in the Chinese city of Qingdao, dismissed the G7 statement as "creative babbling" and challenged accusations that Moscow was behind the poisoning of former double agent Sergei Skripal and his daughter Yulia.
In contrast the G7, the SCO presented a united front against US sanctions.
Pledges worth nearly three billion dollars (2.5 billion euros) for women's and girls' education were announced at the G7 summit.
Trudeau, called it "the single largest investment in education for women and girls in crisis and conflict situations."
The cash, to be spent over three to five years, will be used to train teachers and improve curriculums, track educational data, support innovative education methods, and boost women's and girls' graduation rates in developing countries.