President Trump says the U.S. is pulling out of a joint statement signed by leaders at the end of the latest G7 summit.
Trump tweeted his reversal after what he called "false statements" by Canadian Prime Minister Justin Trudeau, who he labeled "dishonest and weak."
It comes after Trudeau explained his position at a news conference in which he outlined the difficulties in moving forward with the North American Free Trade Agreement.
"I highlighted that it was not helping in our renegotiation of NAFTA and that it would be with regret but it would be with absolute certainty and firmness that we move forward with retaliatory measures on July 1st, applying equivalent tariffs to the ones that the Americans have unjustly applied to us," Trudeau told reporters.
But Trump remains firm in his determination to apply tariffs in a situation he believes is unfair to America's economy.
"It's going to change," said Trump. "I mean it's not a question of 'I hope it changes'. It's going to change, 100 percent. Tariffs are going to come way down because people cannot continue to do that. We are like the piggy bank that everybody’s robbing and that ends."
G7 member countries say that despite the sharp tensions they had signed the joint statement advocating a "rules-based trading system".
Trump also broke with other G7 leaders by calling for Russia to be re-admitted to the group.