TORONTO — Canadian Prime Minister Justin Trudeau said Monday his government could stop doing business with Boeing if the U.S. company doesn’t drop a trade complaint against Canadian plane-maker Bombardier.

Trudeau said Canada “won’t do business with a company that’s busy trying to sue us and put our aerospace workers out of business.”

When Trudeau came to power, part of his platform was to cancel a long-planned F-35 joint strike fighter buy and instead look to Boeing’s F/A-18 as a cheaper alternative. Canada had been in talks to purchase 18 Super Hornet fighter jets from U.S. aerospace giant Boeing, but those have been on hold because of the Bombardier dispute.

Trudeau’s comments are Canada’s strongest yet.

Chicago-based Boeing’s complaint claims Bombardier’s new C Series passenger aircraft receives Canadian government subsidies that give it an advantage internationally.

The complaint prompted a U.S. Commerce Department anti-dumping investigation that could result in penalties for Bombardier. A preliminary decision is expected next week and a final decision could include financial penalties.

Trudeau spoke during a news conference with British Prime Minister Theresa May.

Bombardier is also a major employer in Northern Ireland, with more than 4,000 workers in Belfast. May said she brought up the issue with U.S. President Donald Trump in a recent telephone call and said she’ll reiterate Bombardier’s importance to Northern Ireland when she meets with Trump this week.

Boeing petitioned the U.S. Commerce Department and the U.S. International Trade Commission to investigate subsidies of Montreal-based Bombardier’s C Series aircraft. Boeing says Bombardier has received more than $3 billion in government subsidies that let it engage in “predatory pricing.”

Brazil has also launched a formal complaint to the World Trade Organization over Canadian subsidies to Bombardier. Sao Paolo-based Embraer is a fierce rival of Bombardier’s.

The Quebec government invested $1 billion in exchange for a 49.5 percent stake in the C Series last year. Canada’s federal government also recently provided a $275 million loan to Bombardier, which struggled to win orders for its new medium-size plane.

But Bombardier won a 75-plane order for the C Series from U.S.-based Delta Air Lines in 2016. Bombardier said its planes never competed with Boeing in the sale to Delta.

Canadian Defence Minister Harjit Sajjan previously said Boeing’s action against Bombardier is “unfounded” and not the behavior of a “trusted partner.” He said buying the Super Hornet fighter jets “requires a trusted industry partner.”

Interestingly, just last week, the Defense Security Cooperation Agency announced that Canada had been cleared to buy 18 of the fighter jets, for an estimated cost of $5.23 billion. 

Boeing spokesman Daniel Curran said in a statement that “Boeing is not suing Canada,” emphasizing that its issue is specifically with the “absurdly low” prices Bombardier is able to sell its planes at thanks to what Boeing describes as a “violation” of trade law.

“We like competition. It makes us better. And Bombardier can sell its aircraft anywhere in the world. But competition and sales must respect globally-accepted trade law,” Curran said.

Bombardier minced no words in its own statement, posted online under the header of “Boeing’s Hypocrisy.”

“Boeing’s self-serving actions threaten thousands of aerospace jobs around the world, including thousands of U.K and U.S. jobs and billions of purchases from the many U.K. and U.S. suppliers who build components for the C Series,” the company statement reads.

Aaron Mehta in Washington contributed to this report.