QUEBEC CITY — NYT  President Trump said Saturday that he brought up with America’s closest allies the dramatic prospect of completely eliminating tariffs on goods and services, even as he threatened to end all trade with his counterparts if they don’t stop what he says are unfair trade practices.

Speaking to reporters at the end of a contentious weekend meeting of the Group of 7 nations in a resort town outside of Quebec City,. Trump said that eliminating all trading barriers would be “the ultimate thing.” But he railed about what he called “ridiculous and unacceptable” tariffs on American goods and vowed to get rid of them.

“It’s going to stop. Or we’ll stop trading with them. And that’s a very profitable answer, if we have to do it,” Mr. Trump said, adding that “We’re like the piggy bank that everybody’s robbing and that ends.”

Trump’s comments came during a wide-ranging news conference as he prepared to depart for a summit in Singapore with Kim Jong-un, the reclusive leader of North Korea. Mr. Trump said he will know within the first minute of his face-to-face meeting whether Mr. Kim is serious about eliminating his nuclear weapons and attempting to make peace with the world.

“Just my touch, my feel. That’s what I do,” Trump said. “You know, the way they say you know if you’re going to like somebody in the first five seconds. Did you ever hear that one? Well, I think that very quickly I’ll know whether or not something good is going to happen.”

Mr. Trump said that he expects to “at least start a dialogue” with Mr. Kim, though he suggested, as he has several times recently, that more specific agreements with North Korea could require a series of additional meetings.

The president’s public comments on trade Saturday morning echoed the complaints he made directly to the leaders from Canada, Japan and Europe in private sessions on Friday. Mr. Trump confronted several of the leaders individually, giving examples of how each of their countries had mistreated the United States in his view, whether it be trade barriers or security commitments, according to a European official.

Several of the leaders responded aggressively to Mr. Trump’s demands — as they have repeatedly in public — listing their own complaints about American policies on tariffs and other trade measures, the official said. Several countries have said publicly they will retaliate against the United States’ new steel and aluminum tariffs with increased tariffs of their own.

“If they retaliate, they’re making a mistake,” Mr. Trump said, suggesting that the trade imbalance between the United States and those countries would make tariff increases more destructive for their economies.

In his remarks to questions on Saturday, Mr. Trump repeatedly insisted that the private discussions with his counterparts had been positive, saying that "the relationship that I’ve had with the people, the leaders of these countries has been — I would really rate it on the scale of zero to 10, I would rate it a 10.”

But the president also repeatedly made clear his level of anger about the longstanding trade policies that he said have hurt America’s workers and undermined the country’s national security by weakening America’s “balance sheet.”

Mr. Trump said that the United States continues to renegotiate the North American Free Trade Agreement with Mexico and Canada, which he has said is one of the worst trade deals that the United States ever agreed to.

On Saturday, he said that the United States might have to negotiate separate trade deals with Mexico and Canada if they can’t reach a three-way agreement to make the broader trade agreement fair for Americans.

But he repeatedly returned to his broader complaints about trade practices around the world, insisting that it was the fault of past American leaders who had agreed to deals that benefited other countries more than the United States.

He complained that American dairy farmers are being treated unfairly by Canada, saying that “the United States pays tremendous tariffs on dairy, as an example, 270 percent. Nobody knows that,” he said “We don’t want to pay anything. Why should we pay?”

The president also said that farmers in the United States have been hurt for a long time by trade barriers that make it harder for them to sell their goods to other countries.

“You look at our farmers. For 15 years, the graph has gone just like this, down,” he said.

“I blame our leaders,” he said. “In fact, I congratulate the leaders of other countries for so crazily being able to make these trade deals that were so good for their country and so bad for the United States. But those days are over.”

Mr. Trump said some of the other leaders he met with during the Group of 7 summit appeared to admit that their trade arrangements with the United States were unfair.

[caption id="attachment_84665" align="alignleft" width="300"] Trump and smiling Justin TRudeau[/caption]

“A lot of these countries actually smile at me when I’m talking,” he said. “And the smile is, ‘we couldn’t believe we got away with it.’ That’s the smile.”

That assessment by Mr. Trump stands in contrast to the public statements by those leaders, who have repeatedly insisted that they will not accept the kinds of tariffs that Mr. Trump has imposed on their industries.

In addition to trade, Mr. Trump also took questions about his call for Russia to be reinstated as a member of the Group of 7 nations, despite having been expelled four years ago in the wake of Russia’s invasion of Ukraine.

Asked whether Russia should be allowed to rejoin the group — which would be renamed the Group of 8 — even if Russia has not withdrawn from Ukraine, Mr. Trump said yes.

“I would rather see Russia in the G-8 as opposed to the G-7,” he said. “I would say that the G8 is a more meaningful group than the G-7. Absolutely.”

Mr. Trump also blamed former President Barack Obama for Russia’s invasion, in which the country sent troops into Crimea. Mr. Trump said that it was Mr. Obama who should take responsibility for Russia’s actions.

“Crimea was let go during the Obama administration, and you know, Obama can say all he wants, but he allowed Russia to take Crimea,” the president said. “I may have had a much different attitude, but, so, you really have to ask that question to President Obama. You know, why did he do that?”

In fact, in the wake of the Russian invasion in 2014, it was Mr. Obama who led the other six nations in the Group of 7 to expel Russia in a joint statement known as The Hague Declaration.

During the news conference, Mr. Trump also lashed out at the news media. In response to a question from a CNN reporter about his relationships with the foreign leaders, the president dismissed the question.

“I figured. Fake news CNN. The worst,” Mr. Trump said. “The relationship that I’ve had is great. So you can tell that to your fake friends at CNN.”