Diplomacy cannot be dictated by "fits of anger", French President Emmanuel Macron warned after a G7 summit in Canada ended in acrimony.
In tweets, US President Donald Trump described host Justin Trudeau as "dishonest and weak" and retracted his endorsement of the joint communique.
That statement sought to overcome deep disagreements, notably over trade.
Mr Macron's office said France and other EU countries would maintain their support for the final G7 communique.
Germany also said it would abide by the communique.
In recent weeks, trading partners of the US have criticised new tariffs on steel and aluminium imports imposed by the Trump administration.
Saturday's final communique aimed at easing those tensions by advocating a "rules-based trading system".
In a news conference after the summit, the Canadian leader reasserted his opposition to the US tariffs, and vowed to press ahead with retaliatory moves on 1 July.
"Canadians are polite and reasonable but we will also not be pushed around," he said.
Tweeting en route to his next summit in Singapore, Mr Trump said he had instructed US officials "not to endorse the communique as we look at tariffs on automobiles".
He said the move was based on Mr Trudeau's "false statements... and the fact that Canada is charging massive tariffs to our US farmers, workers and companies".
Mr Trudeau's office responded by saying the prime minister had said nothing he had not said before, both in public and in private conversations with Mr Trump, reports BBC.
