Washington, Jan 30 (AP) President Donald Trump on Thursday threatened Canada with a 50% tariff on any aircraft sold in the U.S., the latest salvo in his trade war with America's northern neighbour as his feud with Prime Minister Mark Carney expands.

Trump's threat posted on social media came after he threatened over the weekend to impose a 100% tariff on goods imported from Canada if it went forward with a planned trade deal with China. But Trump's threat did not come with any details about when he would impose the import taxes, as Canada had already struck a deal.

In Trump's latest threat, the Republican president said he was retaliating against Canada for refusing to certify jets from Savannah, Georgia-based Gulfstream Aerospace.

Trump said the U.S., in return, would decertify all Canadian aircraft, including planes from its largest aircraft maker, Bombardier. “If, for any reason, this situation is not immediately corrected, I am going to charge Canada a 50% Tariff on any and all Aircraft sold into the United States of America,” Trump said in his post.

Trump said he is “hereby decertifying" the Bombardier Global Express business jets. There are 150 Global Express aircraft in service registered in the U.S., operated by 115 operators, according to Cirium, the aviation analytics company.

Bombardier and Gulfstream are head-to-head rivals, with the Global series battling for market share against Gulfstream's latest models.

Bombardier said in a statement that it has taken note of the president's post and is in contact with the Canadian government. The Montreal-based company said its aircraft are fully certified to Federal Aviation Administration standards and it is expanding U.S operations.

“Thousands of private and civilian jets built in Canada fly in the U.S. every day. We hope this is quickly resolved to avoid a significant impact to air traffic and the flying public,” the company said.

Spokespeople for the Canadian government didn't respond to messages seeking comment Thursday evening.

John Gradek, who teaches aviation management at McGill University, said certification is about safety and it would be unprecedented to decertify for trade reasons.

“Certification is not trivial. It is a very important step in getting planes to operate safely,” Gradek said. “Somebody is not picking on the Gulfstream. Decertification for trade reasons does not happen." Gradek said many Gulfstreams have been certified for years in Canada.

“This is really a smokescreen that's basically throwing up another red flag in the face of Mr. Carney," Gradek said. “This is taking it to the extreme. This is a new salvo in the trade war." The U.S. Commerce Department previously put duties on a Bombardier commercial passenger jet in 2017 during the first Trump administration, charging that the Canadian company was selling the planes in America below cost. The U.S. said then that Bombardier used unfair government subsidies to sell jets at artificially low prices.

The U.S. International Trade Commission in Washington later ruled that Bombardier did not injure U.S. industry.

Bombardier has since concentrated on the business and private jet market in its Global and Challenger families of planes. Both are popular with individual owners and businesses as well as fractional jet companies like NetJets and Flexjet. If Trump cuts off the U.S. market it would be a major blow to the Quebec company.

Treasury Secretary Scott Bessent warned Carney on Wednesday that his recent public comments against U.S. trade policy could backfire going into the formal review of the U.S.-Mexico-Canada Agreement, the trade deal that protects Canada from the heaviest impacts of Trump's tariffs.

Carney rejected Bessent's contention that he had aggressively walked back his comments at the World Economic Forum during a phone call with Trump on Monday.

Carney said he told Trump that he meant what he said in his speech at Davos, and told him Canada plans to diversify away from the United States with a dozen new trade deals.

In Davos at the World Economic Forum last week, Carney condemned economic coercion by great powers on smaller countries without mentioning Trump's name. The prime minister received widespread praise and attention for his remarks, upstaging Trump at the gathering.

Besides Bombadier, other major aircraft manufacturers in Canada include De Havilland Aircraft of Canada, which makes turboprop planes and aircraft designed for maritime patrols and reconnaissance, and European aerospace giant Airbus. Airbus manufactures its single-aisle A220 commercial planes and helicopters in Canada. (AP) AMS

Aircraft subject to a threatened 50% tariff and decertification amid a certification dispute between the U.S. and Canada. President Trump threatened a 50% tariff on aircraft sold into the United States and said he would decertify Canadian aircraft, including Bombardier's Global Express jets, as retaliation for Canada's refusal to certify Gulfstream aircraft; the announcement lacked procedural detail, raised unprecedented safety and regulatory concerns, and follows prior U.S. duties and an ITC finding addressing related subsidy and injury claims.