Canada is hitting back, and imposing retaliatory tariffs on up to 12 billion US dollars worth of steel, aluminum and other products from the US. The announcement was made hours after Washington announced the tariffs on Canadian metal would take effect from Friday. Canada is the largest exporter of aluminum to the United States. The country's tariffs are set to go into effect on July 1 and stay in place until the US lifts its own measures.

JUSTIN TRUDEAU CANADIAN PRIME MINISTER "Let me be clear. These tariffs are totally unacceptable. For 150 years, Canada has been the United States' most steadfast ally."

CHRYSTIA FREELAND CANADIAN FOREIGN MINISTER " This is the strongest trade action Canada has taken in the post war era. This is a very strong response. It is a proportionate response. It is perfectly reciprocal. But I really want to assure you to assure Canadians-this is a very strong Canadian action in response to a very bad US decision."