A full-blown trade war between the U.S. and Canada could lead to a recession in both countries, economist says.

The proposed tariffs, if applied to oil and gas, could hammer Canada's economy and hike prices at the pump for Americans, analysts say.

Trump said in a post to Truth Social on Monday that one of his first executive orders would be to hit Mexico and Canada with a blanket 25% tariff. Mexico and Canada are the second and third top suppliers of goods to the U.S., according to the Office of the U.S. Trade Representative. The U.S. imports the most goods from China.