NEW YORK/OTTAWA – US President Donald Trump on Tuesday ordered Canadian products removed from US government contract lists in response to Canada's counter-tariffs.

"I am hereby directing the GSA (General Services Administration), working with the USTR (United States Trade Representative), to take all necessary steps to REMOVE Canadian-origin products from GSA's Multiple Award Schedules unless Canada restores full and fair reciprocity for American Farmers and Companies," Trump wrote in a post on Truth Social.

"Canada doesn't let our Great Dairy Farmers sell into the Canadian Market, and that the only reason Canada makes Autos is because of previous disastrous Trade Agreements while other Presidents were in Office," Trump said. "Canada has been ripping us off for years."

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"The Canadian Government, including Canadian Provinces, have banned American Small Businesses and Companies from selling into their Government Procurement Markets," Trump said. "That is not reciprocity, it is a Canadian Trade Scam."

"From now on, NO RECIPROCITY - NO ACCESS!" Trump declared.

The order comes amid escalating trade tensions between the United States and Canada. The United States imposed 50 percent tariffs on about $20 billion worth of Canadian goods, effective Aug 22, prompting Canada to retaliate with matching tariffs on an equivalent value of US imports, which took effect Tuesday. 

Canadian PM calls for national unity

Also on Tuesday, Canadian Prime Minister Mark Carney called for national unity to navigate the trade conflict with the United States, as Canada's retaliatory tariffs on US imports took effect early in the morning.

"Every time we choose to buy Canadian, travel in Canada, we're sending a message that nobody in this country is in the stands. Forty million of us are on the ice," Carney said in his latest "Forward Guidance" national video address.

Trade negotiations between Canada and the United States collapsed in late August, after Washington imposed 50 percent tariffs on $20 billion worth of Canadian goods. In response, Ottawa began imposing equivalent retaliatory tariffs on US imports, including steel, dairy, agricultural equipment, pulp and electronics.

READ MORE: Canada announces counter-tariffs on over 700 US goods

"There's always a cost to action. But it doesn't come close to the cost of standing still," Carney said.

Reiterating his position, Carney said that the US side raised unreasonable demands at the 11th hour that threatened Canada's sovereignty and core industrial interests. Canada chose to walk away from a bad deal and implement countermeasures, he added.