UAW said Thursday night that it will strike three of America’s biggest automakers – GM, Ford, and Stellantis – at the same time as of midnight if the companies do not reach tentative labour deals with the auto workers.

Staff at three of America’s biggest carmakers will take strike action, United Auto Workers (UAW) President Shawn Fain said on Thursday night.

Fain announced that work would stop at three plants owned by General Motors, Ford, and Stellantis. “For the first time in our history we will strike all three of the big three at once,” he said.

Current labour contracts are set to expire Thursday night. The UAW said the companies had not put forward acceptable offers.

The fight threatens to trigger higher prices for buyers and major disruption for the motor industry giants.

The strike will start from midnight eastern time Thursday at GM’s Wentzville mid-size truck plant, Ford’s Bronco plant in Michigan, and the Toledo Jeep plant owned by Stellantis.

The UAW says their targeted strike plan – a “Stand Up strike,” as Fain described it – will give them more power in negotiations. “If we strike tonight, I’ll see you on the picket line at Michigan assembly at midnight,” Fain said.

The plants are critical to the production of some of the “Detroit Three’s” most profitable vehicles.

Other facilities will continue to operate, the UAW said but it did not rule out broadening the strikes beyond the initial three targets.

Ford said the UAW had presented its first “substantive” counterproposal a few hours from the expiration of the current agreement. “Unfortunately, the UAW’s counterproposal tonight showed little movement from the union’s initial demands,” it said.

With the deadline looming Thursday evening, the White House said President Joe Biden had spoken to leaders of the union and the automakers.

The UAW had sought a 40% pay increase for its roughly 140,000 members over four years, noting a comparable rise in pay for company leaders.

Other demands included:

Talks between both sides, which kicked off in July, were tense from the start, with Fain forgoing the symbolic handshake with executives that has traditionally launched negotiations. Last month, 97% of members voted to authorise a strike.

As of Wednesday, the three companies had upped their initial proposals, with Ford offering a 20% hike in pay over the contract term, GM offering 18%, and Stellantis, the owner of Jeep and Chrysler, 17.5%, Fain said.

Ford’s CEO Jim Farley told reporters earlier this week that he hoped to avoid a strike but there was a limit to what the company was willing to concede

A 10-day strike by all workers at the three firms could cost the automakers nearly $1bn (£800m) and workers nearly $900m in lost wages, estimates by the Anderson Economic Group say. It said the total hit to the economy could amount to more than $5bn, as the effects of the strike spread.

Ford, GM, and Stellantis together account for about 40% of US car sales, though their share has dropped sharply over the last quarter of a century, as foreign firms such as Toyota make inroads.

The last time the US car industry faced a strike was in 2019, when GM workers walked off the job for six weeks.