France has said international cooperation "cannot be dictated by fits of anger"
Donald Trump has refused to sign off on the final G7 communique, and hit out at Canadian Prime Minister Justin Trudeau.
It brought the summit to a dramatic close, following tensions between the US and its allies over the steel and aluminum tariffs recently imposed by the Trump administration.
President Trump left the gathering in Canada early on Saturday to travel to Singapore for his summit with North Korea's Kim Jong Un.
Speaking after the US leader's departure, Mr Trudeau observed: "Canadians, we're polite and reasonable... but we also will not be pushed around.
"I reiterated to President Trump that these tariffs threaten to harm industry and workers on both sides of our border".
It prompted a seemingly heated response from President Trump, who tweeted his reaction from Air Force One - accusing a "meek" Trudeau of "false statements":
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) June 9, 2018
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) June 9, 2018
The New York Times reports that journalists on board Air Force One had been told minutes earlier that the US would indeed sign the final G7 statement.
President Trump's national security advisor John Bolton, meanwhile, claimed "other countries expect America will always be their bank" - and posted a photo of what appeared to be a lively exchange between Trump and other world leaders.
Other G7 leaders had also publicly and privately criticised Trump's controversial tariffs.
France's Emmanuel Macron insisted steel and aluminum imports do not pose a threat to US national security - the reason the White House has cited for implementing the tariffs.
In a statement quoted by AFP after US support for the communique was withdrawn, Mr Macron's office said: "International co-operation cannot be dictated by fits of anger and throwaway remarks.
"We spend two days working out a [joint] statement and commitments. We are sticking to them and whoever reneges on them is showing incoherence and inconsistency."
"Let's be serious and worthy of our people. We make commitments and keep them."
British Prime Minister Theresa May, meanwhile, said there had been "difficult conversations and strong debate" at the summit, saying leaders registered "our deep disappointment at the unjustified decision by the US to apply tariffs".
While acknowledging there would be EU retaliation, she noted the need to avoid a "continued tit-for-tat escalation".
The G7 communique has been published by the Canadian government.
In one section, it states: "Canada, France, Germany, Italy, Japan, the United Kingdom and the European Union will promote the fight against climate change through collaborative partnerships and work with all relevant partners."
However, the United States view on climate change receives a separate, individual paragraph.