President Donald Trump late Thursday threatened a 35% tariff on goods imported from Canada, a dramatic escalation in an on-again, off-again trade war with America’s northern neighbor and one of its most important trading partners.

The president revived his discredited claims about fentanyl entering the U.S. from Canada to justify his latest proposed rate of 35 percent.

WASHINGTON (AP) — President Donald Trump said in a letter that he will raise taxes on many imported goods from Canada to 35%, deepening a rift between two North American countries that have suffered a debilitating blow to their decades-old alliance.