Canadian Prime Minister Justin Trudeau said on Saturday that all members of the Group of Seven had signed on to a joint statement, ending speculation that the United States could be excluded from such a communique.
Trump responded by deriding Trudeau as "very dishonest and weak" and said the U.S. would not endorse the joint the statement.
It is an annual event bringing together Canada, the U.S., the UK, France, Italy, Japan and Germany, which represent more than 60% of global net worth between them.
Trump planned to leave the summit on Saturday before it discussed climate change and the health of oceans, underlining fractures in the G7 exacerbated by USA trade tariffs. Mexico and the European Union have also planned retaliatory tariff packages.
Once again, he emphasized that the days of the US getting the short end of the stick in its trading relationships with the world were over under his watch.
The president said the USA was "pretty close" to reaching an agreement on the North American Free Trade Agreement with Canada and Mexico and had discussed two types of sunset provisions in which any of the countries could leave the deal.
The EU said it will impose the "rebalancing" tariffs on about $3.3 billion (2.8 billion euros) worth of US steel, bourbon, agricultural products including sweet corn, orange juice, cranberries and certain clothing made of cotton.
"No tariffs, no barriers, that's the way it should be, and no subsidies", Trump said during a 30-minute press conference on the sidelines of the meeting in La Malbaie, Quebec. Canada's average tariff for imported goods is 3.1 percent, and the EU's average tariff for imported goods is 3 percent.
"His message from Quebec to Singapore is that he is going to meld the industrial democracies to his will - and bring back Russian Federation", said Steve Bannon, Trump's former campaign and White House adviser.
After two days of often fierce arguments between the United States and both the summit hosts and Europe, the joint statement attempted to paper over their cracks.
Trump said the G7 leaders were united in their approach to the "threat of Iran" and committed to controlling the country's "nuclear ambitions".
She said: "Where we disagree with our allies on something it is right that we say so, and air the issue openly and frankly".
"He's happy", said Trump, to laughter. "With that being said I think we'll probably easily make a deal".
French President Emmanuel Macron described it as a good first step that represented the G7 nations' desire to stabilise the situation. "And we have very, very strong measures that take care of that. the numbers are so astronomically against them. we win that war a thousand times out of a thousand".
The German leader said there was broad agreement among G7 leaders that tariffs and other trade barriers should be reduced.
Meanwhile on Saturday, US President Donald Trump said that some of the G7 countries spoke in favor of Russia's return to the format, and he personally believed that the G8 would be more meaningful for the world. We're looking for peace in the world.
Trump withdrew the USA from the Paris climate accord and his attendance of a G7 session on the issue was in question well into the last minute.
US President Donald Trump boards Air Force One prior to departure from Canadian Forces Base Bagotville in Canada, June 9, 2018.