Finance ministers from six of the world’s largest economies — Germany, Canada, United Kingdom, France, Italy and Japan — condemned President Donald Trump’s unilateral decision to slap tariffs on steel and aluminum on its allies at a conference in Whistler, Canada.

U.S. Treasury Secretary Steven Mnuchin appeared isolated at the Finance Minister’ Meeting shortly before the G7 summit. The top officials expressed their “unanimous concern and disappointment” and called in a joint statement for “decisive action.” Each country has declared its own plans to get even with the United States.

In an earlier interview with CNBC, Mnuchin said, “There is the potential of a trade war.”

“It is dangerous for growth, dangerous for the economic development of the world, and dangerous for our jobs in the E.U. We will be divided — it will not a G-7, it will be a G-6 plus one,” Finance Minister of France, Bruno Le Maire, told Bloomberg Television.

“There was an important difference of opinion,” Canadian Finance Minister Bill Morneau told reporters at the closing press conference.

SLIDESHOW: DONALD TRUMP’S 30 CRAZIEST TWEETS

Justin Trudeau, Canada’s Prime Minister, told NBC News on Sunday, “The Trump Administration’s decision to place tariffs on Canadian aluminum and steel citing national security issues is “insulting and unacceptable.”

Mnuchin tried to allay the allies fears at the meeting. “This was the G7,” he said. “I think there was a comment out there that it was the G6 plus one. It was not. It was the G7. We believe in the G7. It’s an important group.”

But Mnuchin also said, “President Trump has been very clear in wanting to address trade issues.” “Our objective is to make sure we have fair and balanced trade and that’s what we’re really focused on,” he added.

Just right before the meeting ended, Trump tweeted, “the United States must, at long last, be treated fairly on trade.”

The G7 summit next week in Quebec will show whether Mnuchin was able to bridge the gap between the U.S. and its allies.