US President Donald Trump on Thursday threatened Canada with a 50 percent tariff on any aircraft sold in the US, 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-percent 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 US, 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 percent Tariff on any and all Aircraft sold into the United States of America,” Trump said in his post.

Spokespeople for Bombardier and Canada’s transport minister didn’t immediately respond to messages seeking comment on Thursday evening. (AP)