President Donald Trump plans to leave the Group of Seven summit hours earlier than planned, after a war of words broke out between him and former close U.S. allies over trade.

The U.S. president also said Russia should be brought back into the group of advanced nations. His call for a return to G-8 was echoed by Italy’s new leader, Giuseppe Conte, reports said.

Earlier, in a heated exchange mainly on Twitter, the American leader took aim at France and Canada, escalating his feud with those countries over U.S. tariffs and protectionist policies.

The latest dispute kicked off with comments from France’s president, Emmanuel Macron, who hinted at the threat of U.S. trade “hegemony.”

“You say the U.S. president doesn’t care at all. Maybe, but nobody is forever,” French President Emmanuel Macron told a news conference on Thursday, suggesting no leader holds power indefinitely.

Read:With G-7 united against his trade war, Trump is going it alone

Also read:Heading into G-7, Trump’s Mr. Unpopular on the world stage

In the run-up to the Quebec summit, Macron suggested Trump’s trade moves against allies could turn the club of developed nations into G-6 — Canada, Italy, Germany, France, Japan and U.K. — plus 1.

“The six countries of the G-7 without the United States are a bigger market taken together than the American market. There will be no world hegemony if we know how to organize ourselves. And we don’t want there to be one,” he said Thursday, according to The Wall Street Journal report.

Macron then turned up the heat with posts to Twitter later that day, saying a summit deal excluding the U.S. is a possibility.

That seemed to prompt a response by Trump on Twitter, suggesting Canada and France are using unfair trade practices against U.S. producers.

“Please tell Prime Minister Trudeau and President Macron that they are charging the U.S. massive tariffs and create non-monetary barriers. The EU trade surplus with the U.S. is $151 Billion, and Canada keeps our farmers and others out. Look forward to seeing them tomorrow,” he said in one post.

The U.S. leader then hit out at Canada in particular, describing Trudeau as “indignant” and accusing his country’s neighbor of “killing our Agriculture.”

A few hours later, Trump took wider aim at the European Union, claiming the bloc also pursued unfair trade practices against the U.S. and urging them to lift trade barriers.

He didn’t let the matter drop, returning to the fray early Friday morning with another tweet on Canada’s dairy tariffs.

Trump has chafed at attending a summit where he will be surrounded by critics on all sides, seeing the G-7 summit as a “distraction” from his meeting with North Korean leader Kim Jong Un on Tuesday, reports say.

Late Thursday, the White House said that Trump will step out of the Quebec summit mid-morning Saturday, bound for Singapore to meet Kim. An aide will stand in for the president in the sessions he’s skipping, on climate change and the environment.

Speaking in Washington Friday, Trump called for the group to reinstate Russia. The country’s membership of the then G-8 group was suspended after the annexation of Crimea in 2014.

His comments were backed by Italy’s new prime minister, who is making his debut in the group at the meeting. “I agree with President Donald Trump; Russia should return to the G-8,” Conte said, according to a report in Italian newspaper Repubblica.

Meanwhile, Russian President Vladimir Putin has asked Austria’s chancellor to organize a meeting with Trump in Vienna this summer, and the White House is pondering the offer, a senior European official said.