US President Donald Trump has attacked Canada after Prime Minister Mark Carney announced retaliatory tariffs on US steel, dairy and other goods, to take effect September 8. Trump said on Truth Social that Canada wants "the benefits of being a State, without being one" and has charged American farmers "massive amounts of tariffs for many years."

The escalation follows the collapse of trade negotiations on Friday. The US imposed 50 per cent tariffs on about $US20 billion of Canadian goods on Saturday, covering wine, furniture, dairy, cement, clothing and fishing equipment. Canada's retaliatory tariffs will be "dollar for dollar" on US imports, Carney said, ABC business (AU) reports.