Prime Minister Justin Trudeau vowed a "firm" and unwavering defense of Canadian interests in the face of US trade attacks, he said Friday.
"We're going to continue to work very, very hard to defend Canada's interests," he said.
In late April, the United States imposed a duty on timber imported from Canada and threatened similar sanctions on Canadian dairy products.
Then on Thursday, the U.S. Department of Commerce launched an investigation at the request of aerospace manufacturer Boeing into alleged dumping of aircraft built by its Canadian rival Bombardier, with Canadian government financial support, into the U.S. market.
On all of these issues, "we will always be resolute and firm in how we stand up for Canadian interests," Trudeau said.
"On the issue of aeronautics, we will always defend Canada's companies... and Canada's workers."
On Thursday, Foreign Minister Chrystia Freeland threatened to cancel Ottawa's purchase of Boeing fighter jets if the U.S. did not back off its attacks on Bombardier.
The same day, the US government formally launched the process to renegotiate the North American Free Trade Agreement.
U.S. President Donald Trump has assailed the continental trade pact as "the worst trade deal maybe ever signed anywhere."
NAFTA negotiations between Canada, Mexico and the United States are to formally start in August after a 90-day consultation process.