"We have to have deals that are fair", Trump said.
Trump said that he also discussed the possibility of Russian rejoining the summit and immigration.
The US president also repeated his call for Putin to join the other leaders around the summit table.
Russian Federation was thrown out of the group in 2014 over the annexation of Crimea.
Despite earlier reports of a rant over trade from Trump, he said the meeting "was not contentious" and called the relationships between the leaders "outstanding". We're looking for peace in the world.
Mr Trump is expected to leave the summit early and travel to Singapore ahead of a meeting there with the North Korean leader Kim Jong-un on Tuesday.
Canada's Foreign Minister Chrystia Freeland expressed outrage that Trump had invoked a national security justification for his global tariff on steel and aluminum imports, even those from close USA allies.
Republican Sen. Ben Sasse of Nebraska said Trump's comments on eliminating tariffs among G7 nations would be "tremendous news" if the President is serious about the issue, adding, "I would happily carry his bag to every single meeting of those negotiations".
Trump criticized the premise of the question, which came from CNN during a G-7 news conference.
FYI: G7 or Group of Seven is a group consisting of Canada, France, Germany, Italy, Japan, the United Kingdom, and the United States.
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European Council President Donald Trump accused Trump of challenging the "rules-based global order", and suggested his policy "makes no sense at all".
Donald Trump disrupted a G7 breakfast discussion on women's empowerment Saturday morning by showing up late.
"We are ready for this", he said.
Trump did not specify how the US's allies responded to his proposal.
"I would say that the G8 is a more meaningful group than the G7, absolutely", Trump said.
On 1 June, the United States imposed a 25% tariff for steel and 10% for aluminium on imports from the EU, Canada, and Mexico.
Trump was last to arrive for the G7 working breakfast, walking into the room when the summit's host, Canadian Prime Minister Justin Trudeau, had almost finished his welcome and presentation speech, Efe reported.
In response, Canada, Mexico and the European Union said they were putting in place their own retaliatory measures.
"After calling out Trudeau and Macron before the summit, he took a different approach on Saturday, "[congratulating] he leaders of other countries for crazily being able to make these trade deals that were so good for their countries and bad for the United States" and chastising his predecessors for allowing the U.S.to be taken advantage of.
Trudeau has made the issue of gender equality a priority for the gathering.
The president went into the meeting under intense pressure from foreign leaders after he slapped high tariffs on steel and aluminum imports, citing USA national security needs.