By JOSH BOAK, Associated Press

WASHINGTON (AP) — President Donald Trump says that he will double his planned tariffs on steel and aluminum from 25% to 50% for Canada, escalating a trade war with the United States’ northern neighbor.

Trump says the increase of the tariffs set to take effect on Wednesday is a response to the price increases that the provincial government of Ontario put on electricity sold to the United States.

“I have instructed my Secretary of Commerce to add an ADDITIONAL 25% Tariff, to 50%, on all STEEL and ALUMINUM COMING INTO THE UNITED STATES FROM CANADA, ONE OF THE HIGHEST TARIFFING NATIONS ANYWHERE IN THE WORLD,” Trump posted Tuesday on Truth Social.

The U.S. stock market promptly fell following the social media post.