US President Donald Trump threatened on Tuesday to eliminate subsidies for General Motors Co in retaliation for the automaker cutting US jobs and plants, and the automaker also took fire from Canadian political and labor leaders for cutbacks there.

"The US saved General Motors, and this is the THANKS we get! We are now looking at cutting all @GM subsidies, including ... for electric cars," Trump said on Twitter.

Trump's harsh words rattled investors, who bid down GM shares by 2.6 percent on Tuesday after sending them up on Monday in response to the automaker's cost-cutting. Separately, Canadian Prime Minister Justin Trudeau called Trump to discuss GM's actions, according to union leaders.

The wrath of the leaders of the United States and Canada dramatized the challenges GM and its Detroit rivals will face as they restructure to cope with the most dramatic technology and market shifts in decades.

Trump has made boosting auto jobs a key priority during his almost two years in office and has often attacked automakers on Twitter for not doing enough to boost US employment. The president on Tuesday escalated his attacks on GM's plan to cut 15,000 jobs and mothball five North American factories, including four in the United States. Among the four US factories on the block is a car factory in northeast Ohio, a state critical to victory in the 2020 presidential campaign.

GM electric vehicles are eligible for a $7,500 tax credit under federal law, but it is not clear how the administration could restrict those credits or if Trump had other subsidies in mind.

GM said in a statement following Trump's comments that it was "committed to maintaining a strong manufacturing presence" in the United States after investing $22 billion in operations here since 2009 and will add new jobs in electrification and autonomous vehicles.

The cuts will "position the company for long-term success and maintain and grow American jobs," GM said, adding that many workers at impacted plants will be able to move to other GM factories.

GM Chief Executive Mary Barra spoke to Trump over the weekend to discuss the cuts and was at the White House on Monday to meet with economic adviser Larry Kudlow.

Kudlow told reporters Tuesday that the administration had helped GM with fuel efficiency standards and other regulations.

"We’ve done this to help you and I think his disappointment is, it seems like that they kind of turned his back on him," Kudlow said.