U.S. President Donald Trump says Canada has "outsmarted" the U.S. for a long time but his administration is "not going to put up with it" when it comes to trade. Trump also said he had “no fear” of a trade war with Canada.

“They have a tremendous surplus with the United States. Whenever they have a surplus, I have no fear,” said Trump during a ceremony to sign an executive order to help promote the U.S. agriculture sector.

“People don’t realize it but Canada has been very rough on the United States,” said Trump. “Everyone thinks of Canada being wonderful, and so do I — I love Canada — but they have outsmarted our politicians for many years.”

Trump has been railing against Canada's decision to change its policy on pricing domestic milk to cover more dairy ingredients, leading to lower prices for products, including ultra-filtered milk.

His administration moved Monday to impose a 20-per-cent tariff on softwood lumber entering the U.S. from Canada, escalating an intensifying trade dispute between the two countries.