By Jarrett Renshaw, Daphne Psaledakis and David Lawder WASHINGTON (Reuters) - President Donald Trump said on Sunday the sweeping tariffs that he has imposed on Mexico, Canada and China may cause "short term" pain for Americans as global markets reflected concerns the levies could undermine growth and reignite inflation.

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.

President Donald Trump on Sunday defended his decision to impose broad tariffs on Canada, Mexico and China, acknowledging they may cause “some pain” but claiming it “will all be worth the price,” as the import taxes have been widely condemned by business groups and economists who warn they’ll raise prices for American consumers.