The communique, which had appeared to have papered over the cracks that surfaced so uncharacteristically at the G7, said the leaders of the United States, Canada, Britain, France, Italy, Germany and Japan were agreed on the need for "free, fair, and mutually beneficial trade" and the importance of fighting protectionism.
Mr Trump roiled the G7 meeting in Canada by first agreeing to a group statement on trade, only to withdraw from it while complaining that he had been blindsided by Canadian Prime Minister Justin Trudeau's criticism of his tariff threats at a summit-ending news conference.
In this photo made available by the German Federal Government, German Chancellor Angela Merkel, center, speaks with US President Donald Trump, seated at right, during the G7 Leaders Summit in La Malbaie, Quebec, Canada, on Saturday, June 9, 2018. The U.S. president seems to be alluding to a discordance between Justin Trudeau overall temperament during the meeting and his stance on U.S. Tariffs between the neighbouring countries. He also said that because of Trudeau's comments, he instructed USA trade representatives to not sign the communique the G-7 leaders had agreed upon expressing the need for "free, fair, and mutually beneficial trade".
Trudeau announced on Saturday that all G7 members had endorsed the joint communique; however, he noted that the US tariffs are "insulting" and Canada "will not be pushed around".
Mr Trudeau said he had told Mr Trump "it would be with regret but it would be with absolute clarity and firmness that we move forward with retaliatory measures on July 1, applying equivalent tariffs to the ones that the Americans have unjustly applied to us".
Having castigated his host and neighbour and disrupted the alliance of democracies, Trump tweeted about being on his way to Singapore "where we have a chance to achieve a truly wonderful result for North Korea and the World".
'Fool Trade': Trump continues to rip G7 in tweetstorm
Kudlow said Kim must not see "American weakness" on the eve of the Tuesday summit.
She also said the European Union would "act" against the USA trade measures. He said that Canada has to stand up for itself. Navarro also said Trump attending the G7 in Canada was a "courtesy" to Trudeau and that the President had "bigger things on his plate" in Singapore.
Trudeau, who announced that the G7 had issued a joint communique, had to suffer the wrath of Trump.
Shaun Osborne, chief FX strategist at Scotiabank, said the market's reaction to sell the Canadian dollar following Trump's latest tweets reflect a belief that a NAFTA deal is further away now.
"We would hope that the United States will similarly honour the commitments that they have made", he said, speaking before a parliamentary statement on the summit by Prime Minister Theresa May. She also doubted if the USA leader still has what she called "the spirit of G7".
He reiterated his longstanding view that the USA has been taken advantage of in global trade, adding, "We're like the piggy bank that everybody's robbing, and that ends".