Updated 3:14 p.m. | President Donald Trump on Saturday said North Korean leader Kim Jong Un has a “one-time shot” at a denuclearization deal and downplayed tensions with some of America’s closest allies even as he threatened to sever all trade ties with them.

Trump predicted he will know if Kim is serious within 60 seconds of their scheduled meeting Tuesday in Singapore, and reiterated his stance that Russia should rejoin what is now known as the G-7 group of wealthy countries. He also left open the possibility of a one-on-one meeting with Russian President Vladimir Putin later this year, even as he and his associates remain under federal scrutiny for possible improper campaign coordination with Russians.

The president addressed the media on his way out — earlier than initially planned — of the G-7 summit in Canada, saying of his coming summit with Kim, “We have to get denuclearization.”

[Analysis: Trump Wanted a Fight. He Found One — With His Allies]

When asked if he has butterflies or a steely resolve when he thinks of the first-ever meeting between a sitting U.S. president and a sitting North Korean leader, he responded, “It’s both.” The acknowledgement of nerves is a rarity for the bluster-prone Trump.

“He won’t have that opportunity again. It will never be there again,” he said of Kim. “It’s a one-time shot.”

Trump, who describes himself as a once-in-a-generation deal-maker, said he should know if the Kim talks will lead to a deal “within the first minute” because of “my touch, my feel — it’s what I do.”

“They’re really working very well with us,” he said of the Kim government. “I say, ‘So far, so good.’ We’ll see what happens,” adding that North Korea has the potential to be a “tremendous place” in a “short” period of time.

Watch: What to Watch as Trump Heads to Historic North Korea Summit

‘Unfair’ deals

On trade, Trump and G-7 leaders such as Canadian Prime Minister Justin Trudeau and French President Emmanuel Macron traded sharp barbs before the summit kicked off. While the U.S. president on Saturday said talks were productive over the roughly 24 hours he was at the summit, he did deliver a stern warning to them in his exit remarks to reporters.

“We are talking to all countries. And it’s going to stop,” he said of what he often calls “unfair” deals and tactics by other governments. “Or we’ll stop trading with them.”

“We’re like the piggy bank that everyone is robbing. And that will end,” Trump said.

The president confirmed he pitched a new G-7 trading framework that would be free of tariffs, subsidies and “barriers.” He used import fees U.S. firms pay on dairy products that go to Canada as an example, saying the northern neighbor charges American companies a rate that is too high and which “hurts” U.S. farms and companies.

“We don’t want to pay anything. Why should we pay? You want tariff-free, no barriers, and you want no subsidies,” Trump said. “That’s the way you learn at the Wharton School of Finance.”

Sen. Ben Sasse of agriculture-heavy Nebraska, who has not been shy to criticize Trump over his trade policies, applauded the president’s pitch.

“If the President is actually serious about leading the expansion of a G-7 no-tariff, free-trade agreement, that’s tremendous, tremendous news —for the U.S. and for the free nations of the world,” the Republican senator said in a statement.  “I would happily carry his bag to every single meeting of those negotiations.”

[(VIDEO) What to Watch as Trump Heads to Historic North Korea Summit]

Trump described his relations with the other G-7 leaders as “a 10” and said talks during the summit were “not contentious.” But he added, “What was strong was the message that this cannot go on.” The president, however, repeated his contention that America’s allies have joined its rivals in treating the U.S. unfairly on trade matters. To that, Sasse sharply objected.

“The path to more trade begins with less whining on the global stage,” he said. “The constant victim-talk doesn’t help anyone.”

“It doesn’t help trade negotiations,” Sasse said. “And it doesn’t help U.S. citizens understand the disruption in our economy that is actually coming from more technology and more automation, not from free trade agreements, which have overwhelmingly benefited American families.”

statement on G7 talks:

“constant victim-talk doesn’t help trade negot’ns & doesn’t help citizens make sense of disruption coming from tech” pic.twitter.com/RvpxSboqX6 — Ben Sasse (@BenSasse) June 9, 2018

On the North American Free Trade Agreement, the president said talks on issues such as sunset clauses are nearing completion. He also said it remains possible the tri-country pact could remain in place, or his administration would seek individual deals with Mexico and Canada.

Russia update

And on Putin, Trump said he has not spoken to the Russian leader “in quite a while.”

The U.S. chief executive earlier this year pitched a one-on-one summit with Putin, but White House officials have had little say when pressed on planning — or if it will even go off.

Trump announced the two sides have discussed Vienna as a possible site for those talks — even as the special counsel continues looking into Russia’s 2016 election meddling and his possible obstruction of justice.

The president again called for Russia to be let back into the organization now called the G-7 after being kicked out over its invasion of the Crimea region of Ukraine.

“I think it would be an asset to have Russia back in,” he said. “We’re looking for peace in the world, we’re not looking to play games.”