What to know as President Donald Trump imposes steep new tariffs on imports from Canada, Mexico and China, prompting retaliation and countermeasures.

This will be the golden age of America! Will there be some pain? Yes, maybe (and maybe not!). But we will make America great again, and it will all be worth the price that must be

Amid warnings of price increases, Canada moved quickly to retaliate, China said it had planned countermeasures and Mexico said it would soon unveil its response.