President Donald Trump said on Sunday the sweeping tariffs that he has imposed on Mexico, Canada and China may cause "some pain" for Americans, as Wall Street and the largest U.S. trading partners signaled hope that the trade war would not last long.

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.

Trump knows the United States has more leverage over its neighbors than they do over his country. But exploiting that position of strength could cause a historic rupture.