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.

And, in a separate NBC News interview, he suggested blanket tariffs on other US trading partners will jump, as well.

The Thursday actions are the latest examples of a whipsaw policy that’s left investors, trading partners, businesses and everyday Americans alike scrambling to make plans even as the economic ground shifts not just from week to week but in some cases from hour to hour.

It wasn’t immediately clear if the new tariffs, set to take effect August 1, would apply to all Canadian goods or if Trump’s threat applied only to the limited number of goods on which the United States currently levies tariffs.

“Throughout the current trade negotiations with the United States, the Canadian government has steadfastly defended our workers and businesses,” Prime Minister Mark Carney said in a statement to X.

“We will continue to do so as we work towards the revised deadline of August 1.”