QUEBEC CITY — President Donald Trump said Saturday that North Korean leader Kim Jong Un has a "one-time shot" to show he's serious about a nuclear disarmament deal.

"I feel that Kim Jong Un wants to do something great for his people and he has that opportunity," Trump said at a press conference just before he departed a G-7 summit in Charlevoix, Canada, for his historic Tuesday rendezvous with Kim in Singapore. "He won't have that opportunity again."

Trump's carrot-and-stick rhetoric on North Korea matched his message for the G-7 on trade. After a week in which he exchanged pointed barbs with some leaders of other G-7 nations — Canada, the U.K., France, Italy, Japan and Germany — Trump said Saturday that he is confident he can get them to rectify trade imbalances he believes are harmful to American workers.

"We're going to fix that situation," he said. "And if it's not fixed, we're not going to deal with these countries."

In particular, Trump said he expects that he will either be able to convince Canada and Mexico to significantly reshape the North American Free Trade Agreement or that he will create new trade deals with each country separately.

But for all Trump's sunny talk about his relationships with G-7 leaders — he rated them a "10" — he left town before the release of a traditional end-of-conference "communique" and then tweeted that he would instruct his aides not to sign it after Canadian Prime Minister Justin Trudeau said there was agreement on seeking free and fair trade.

"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!" Trump wrote on Twitter.

Trudeau had said after Trump's exit that Canada would retaliate against U.S. tariffs.

"Canadians are polite, we're reasonable but we also will not be pushed around," he said.

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

By the end of the day, it was evident that Trump had shaken a long-standing alliance. U.S. allies are not happy about being slapped with tariffs, and several of the countries were dumbstruck by Trump's Friday call for Russia to rejoin the league of economically powerful nations after being expelled for annexing Crimea in 2014.

To add insult to apparent injury, Trump arrived at the conference late on Friday, forcing French President Emmanuel Macron to reschedule a meeting with him, showed up nearly 20 minutes after the planned start of a breakfast session Saturday and bolted out of town several hours before the meeting wrapped up.

Before he left, he reiterated his hope that Russian President Vladimir Putin would be welcomed back into the organization.

"I would rather see Russia in the G-8 as opposed to the G-7," he said. "The G-8 is a more meaningful group than the G-7."

He also blamed his predecessor, President Barack Obama, for the Russian incursion into Crimea.

"Obama can say all he wants, but he allowed Russia to take Crimea," Trump said. "I may have had a much different attitude. Why did he do that?"

But with the G-7 in his rearview mirror, Trump seemed ready to focus on North Korea. At a minimum, he said, he wants to begin a relationship and, he predicted, it won't take him long to figure out whether Kim is genuinely interested in a making a deal that includes denuclearization.

"I think within the first minute, I’ll know — just my touch, my feel," he said.