LA MALBAIE, Quebec >> Exiting a world summit, President Donald Trump delivered a stark warning today to America’s trading partners not to counter his decision to impose tariffs on steel and aluminum imports. But the summit host, Canadian Prime Minister Justin Trudeau, whose nation is among those singled out by Trump, pushed back and said he would not hesitate to retaliate against his neighbor to the south.

“If they retaliate, they’re making a mistake,” Trump declared before departing the annual Group of Seven summit being held in Canada to head for his meeting with North Korea’s Kim Jong Un in Singapore on Tuesday.

Trudeau later said he reiterated to Trump that tariffs will harm industries and workers on both sides of the U.S.-Canada border. He said unleashing retaliatory measures “is not something I relish doing” but that he wouldn’t hesitate to do so because “I will always protect Canadian workers and Canadian interests.”

Despite the sharp differences, Trudeau said all seven leaders had come together to sign a joint declaration despite having “some strong, firm conversations on trade, and specifically on American tariffs.”

Trump’s abbreviated stay at this Quebec resort saw him continuing the same type of tough talk on trade as when he departed the White House, when he accused Trudeau of being “indignant.”

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 international order.

“His message from Quebec to Singapore is that he is going to meld the industrial democracies to his will — and bring back Russia,” said Steve Bannon, Trump’s former campaign and White House adviser. Bannon said China is “now on notice that Trump will not back down from even allies’ complaints in his goal of ‘America First.’”

Speaking today during a rare solo news conference, Trump said he pressed for the G-7 countries to eliminate all tariffs, trade barriers and subsidies in their trading practices. He reiterated his longstanding view that the U.S. has been taken advantage of in global trade, adding, “We’re like the piggy bank that everybody’s robbing and that ends.”

He said U.S. farmers had been harmed by tariffs and other barriers and warned that U.S. trading partners would need to provide him with more favorable terms. “It’s going to stop or we’ll stop trading with them,” he said.

Trump cited progress on reaching an agreement on the North American Free Trade Agreement with Canada and Mexico, saying the final outcome would lead either to an improved trade deal or separate pacts with the two U.S. neighbors. Trump said he was discussing two types of sunset provisions in which any of the countries could leave the deal. A Canadian official said the leaders discussed accelerating the pace of the talks.

But Trudeau objected strenuously to a sunset clause of any length. “If you put an expiry date on any trade deal, that’s not a trade deal. That’s our unequivocal position,” he said.

Prior to his arrival on Friday, the president injected additional controversy by suggesting that the G-7 offer a seat at the table to Russia, which was ousted from the group in 2014. Trump said today that re-admitting Russia to the elite club would be “an asset,” telling reporters, “We’re looking for peace in the world.” Trump said he had not spoken with Russian President Vladimir Putin in a while.

Discussing Russia’s absence, Trump made the vague comment that “something happened a while ago where Russia is no longer in. I think it would be an asset to have Russia back in.” In fact, Russia was expelled from what was then the G-8 after it invaded and annexed Crimea and for its support for pro-Russia separatists in Ukraine.

Trump placed the blame on his predecessor, President Barack Obama. “He was the one who let Crimea get away — that was during his administration,” he said, adding: “Obama can say all he wants, but he allowed Russia to take Crimea. I may have had a much different attitude.”

It was not clear what Trump thought Obama should have done to prevent Putin from sending in Russian troops to seize the Black Sea peninsula from neighboring Ukraine.

Trudeau said he told Trump that readmitting Russia “is not something that we are even remotely looking at at this time.”

Trump departed the annual G-7 gathering after arriving late to a breakfast on gender equity and skipping later sessions on climate change, clean energy and ocean protection. He left before Trudeau announced that the traditional joint statement had been signed by all seven industrialized nations in the group, which in addition to the U.S. and Canada includes Britain, Italy, France, Germany and Japan.

Trump’s recent moves, building on 18 months of nationalist policy-making, left him out of step with the globally minded organization and prompted speculation that the group could fracture into something more like the “G-6 plus one.”

A key question was whether the seven countries could agree on a joint statement of priorities at the conclusion of the meeting. Macron said Thursday on Twitter, “The American President may not mind being isolated, but neither do we mind signing a 6 country agreement if need be.” Trump said Friday he thinks the group will produce a joint statement.

In public, Trump bantered easily with his fellow leaders, but the meeting came at a tense moment in the relationships, with allies steaming over Trump’s new tariffs on imported steel and aluminum from Canada, Mexico and the European Union.

Leading up to the meetings, Trump, Trudeau and French President Emmanuel Macron had suggested the potential for a tough tone, though they were cordial in face-to-face meetings.

Alluding to the tensions as he sat with Macron on Friday, Trump said: “We’ve had, really, a very good relationship, very special. A lot of people wrote a couple of things that weren’t quite true. A little bit accurate, perhaps. We have a little test every once in a while when it comes to trade.”

With Trudeau, Trump joked that “Justin has agreed to cut all tariffs and all trade barriers between Canada and the United States.”

Macron said he and Trump had “open and direct” discussions, adding that he thought there was a way to get a “win-win” outcome on trade. Details remained unclear.