Canada will respond immediately and forcefully if the United States goes ahead with a threat to impose tariffs, Prime Minister Justin Trudeau said on Friday, warning Canadians that they could be facing tough times.

If the president does choose to implement any tariffs against Canada, we're ready with a response — a purposeful, forceful but reasonable immediate response,' Trudeau said.

"We're ready with a response - a purposeful, forceful but reasonable, immediate response. It's not what we want, but if he moves forward, we will also act," he said in televised remarks, adding that all options were being considered.