India, Aug. 26 -- Canada has struck back against the United States with extensive retaliatory tariffs covering billions of dollars in American merchandise, marking a severe escalation in a trade dispute that threatens to destabilise one of the world's most integrated economic partnerships.

The announcement by Ottawa follows the sudden breakdown of intensive bilateral trade negotiations and subsequent sweeping levies enacted by US President Donald Trump over the weekend. Canadian officials confirmed that duties ranging from 15 percent to 50 percent will target more than 700 American goods, creating mounting uncertainty for manufacturers, farmers, and consumers across North America.

The dramatic breakdown in relations occurred after Washi...