Each country now faces crucial decisions about how to proceed.
On the subject of Russia, Trump said he thought it would be "an asset" to have the country in what would be the G8.
The EU and Canada have taken steps to retaliate.
But Sasse said Trump's complaints that other countries have taken advantage of the United States are unfounded, adding that he recommended "less whining on the global stage".
A key question was whether the seven countries could agree on a joint statement of priorities at the conclusion of the meeting.
Trump's call for the elimination of trade barriers come amid fears of an all-out trade war after the U.S. moved ahead with a 25 percent import tax on steel and a 10 percent on aluminum on most countries.
The agreement was a robust response to counteract the hostile actions of nations such as Russian Federation, which interfered in the elections of the United States and some European Union countries through internet sites and social media.
Trump withdrew the United States from the Paris climate accord and his attendance of a G7 session on the issue was in question well into the last minute. "I would say that the G-8 is a more meaningful group that the G-7".
During the Saturday press conference, Trump slammed the press for reporting on heightened tensions at the meeting.
Despite the tough words, Trump said his relationship with German Chancellor Angela Merkel, French President Emmanuel Macron and Trudeau is at a "10".
He also defended the wisdom of his controversial tariffs, saying that the USA would win a trade war against its allies because "they do so much more business with us than we do with them".
Mr Trump's imposition of tariffs on steel and aluminium imports has sparked anger, with even U.S. allies falling subject to them.
After arriving late, the president was expected to leave early to fly to his meeting with Kim Jong-un, the North Korean leader.
Trump says they will either have a better agreement on NAFTA or two deals involving separate trade deals with both Canada and Mexico.
He said he would know within the first minute if Kim was serious about denuclearization and if he wasn't serious he would walk out of the meeting. Trump credited his intuitive "touch" as a dealmaker. "Fake news CNN", Trump said.
Russian Federation was booted from the conference of the world's leading economies after it invaded Ukraine and annexed Crimea in 2014.
"For us, it was important that we have a commitment for a rule-based trade order, that we continue to fight against protectionism and that we want to reform the WTO", Merkel said.
Mrs May has acted as something of a mediator in heated talks at the worldwide summit in Quebec, pleading with fellow leaders to step back from the brink of a trade war at a session on Friday night. "With that being said, it's been done a long time".
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