Tensions between the United States and its G7 partners over trade and the United States withdrawal from the Iran nuclear deal were rife ahead of the summit which had been dubbed by some as "G6 plus one", referring to an isolated US.
America's closest allies braced for a showdown with President Donald Trump at the G7 summit Friday, as anger at being slapped with trade tariffs by their most powerful member threatened to split the club.
Canada's Foreign Minister Chrystia Freeland expressed outrage that Trump had invoked a national security justification for his global tariffs, even on imports from close U.S. allies.
The US president has made it clear he believes the removal of tariffs against his G7 allies should come at a price - and he doesn't expect the US to pick up the tab.
German Chancellor Angela Merkel sat between Macron and Trump on a sofa, while Trudeau sat to the left of the United States president.
Trump left the meeting early to fly to Singapore for a meeting with North Korean leader Kim Jong Un, describing it as a "mission of peace".
The announcements come as Mr. Trump seeks to make headway on the deep US trade deficit, saying the country has been taken advantage of for too long, and he is fighting back.
The Canadian leader is embroiled in rows with Washington over steel and aluminum and negotiations over the North American Free Trade Agreement. "I think within the first minute I'll know", Trump said.
"It would be with regret, but it would be with absolute certainty 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", Trudeau said.
McConnell: Senate won't pass bill reining in Trump's tariff authority
It's unclear how much Democratic support exists and there's now no commitment their House counterparts would follow suit. Now, Senate Majority Leader Mitch McConnell wants to bring that to an end - and the timing couldn't be more suspect.
Over the course of the summit, the President pushed the narrative that the U.S.is a victim of a trade imbalance, though European leaders rejected these claims.
"The Prime Minister said nothing he hasn't said before - both in public, and in private conversations with the President".
Trump has complained repeatedly - including throughout the summit - about Canada's protected dairy sector, citing 270 percent tariffs that he says stand in the way of American farmers accessing that market.
TRUMP SOT: "We're going to deal with the unfair trade practices".
In his own tweets in French and English, Macron stated that while Trump "may not mind being isolated" the other six leaders meeting in Canada would also not mind signing an agreement among themselves.
"We are focused on everything we accomplished here at the G7 summit", the statement, released by Cameron Ahmad, said.
The summit came during an ongoing trade dispute with China and served as a precursor to the unprecedented meeting with Kim, in which Trump has sought to extend a hand to the Asian autocrat who has long bedeviled the global order.
He said USA farmers had been harmed by tariffs and other barriers and warned that US trading partners would need to provide him with more favorable terms. The statement had been published online before Trump commented. Germany has suggested making accommodations over trade with the United States for fear of triggering a ratcheting up of tensions over cars that would embroil companies like BMW and Mercedes.
"We Europeans and the Japanese are not ready to give up everything to get" Trump's signature, he said, adding that would be a "mistake".