Mr. Trump said the decision came in response to Ontario's move to impose a 25% surcharge on electricity exports to the U.S. Mr. Trump has already imposed a 25% tariff on nearly all imports from Canada, and declared a 25% tariff rate on all steel and aluminum imports from any foreign country.

The government of Ontario is applying a 25 percent surcharge starting Monday on electricity exports to three U.S. states in response to U.S. tariffs on Canada. This surcharge will affect