Trump spars with Trudeau, Macron on trade ahead of G-7 summit

President Donald Trump on Thursday took more jabs at Canada and France on the eve of the G-7 summit.

In a tweet, Trump accused the U.S. allies of levying "massive tariffs" and creating "non-monetary barriers."

French President Emmanuel Macron in a tweet had threatened to exclude U.S. from a joint statement issued every year at the G-7 summit.

"The American President may not mind being isolated, but neither do we mind signing a 6 country agreement if need be. Because these 6 countries represent values, they represent an economic market which has the weight of history behind it and which is now a true international force," Macron tweeted.

On Friday, Trump is scheduled to attend the annual summit and meet with leaders from the U.K., Canada, Japan, Italy, Germany and France. The forum of industrialized economies takes place in Quebec this year.

Also on Thursday night, Trump attacked Trudeau over the dairy industry, claiming that Canada is "killing" U.S. agriculture.

Canada bought 31 percent of U.S. milk exports and 5.3 percent of its cheese exports in 2016, according to data from MIT's Observatory of Economic Complexity.

Tensions between the U.S. and many of its allies were already high after the Trump administration decided late last month to impose tariffs on imports from Canada, Mexico and the European Union, citing national security concerns.

Trudeau responded at the time that it's offensive for the Trump administration to claim that Canada poses a security threat to the United States, given the "the thousands of Canadians who have fought and died alongside their American brothers in arms."

Canada also said it would levy "dollar-for-dollar" retaliatory measures against the U.S. tariffs. Other countries pledged to impose their own retaliatory tariffs.

Trump has repeatedly lashed out at Trudeau on Twitter. Last week, Trump said Canada's trade policies have treated American farmers "very poorly for a long period of time."

Over the weekend, top economic leaders asked Treasury Secretary Steven Mnuchin to relay their "unanimous concern and disappointment" over the tariffs on steel and aluminum imports.

—CNBC's Ted Kemp contributed to this report.