The United Auto Workers (UAW) looks set to escalate strike actions against US car plants on Friday as the union struggles to reach a deal with the automakers General Motors, Stellantis and Ford.

The UAW president, Shawn Fain, announced last week that the union would launch a series of “stand up” strikes at individual car plants after failing to reach agreement over a new union contract with the car companies.

“If we don’t make serious progress by noon on Friday, September 22nd, more locals will be called on to stand up and join the strike,” Fain said this week. “Autoworkers have waited long enough to make things right at the big three. We’re not waiting around and we’re not messing around, so noon on September 22nd is a new deadline.”

The United Auto Workers represents nearly 150,000 autoworkers at the manufacturers but has chosen to select local unions to strike rather than staging a mass walkout.

The strategy preserves the union’s strike fund and aims to leave the companies guessing as to which sites will walk out, building pressure to come to an agreement. The strike is the first time the UAW has walked out at all three automakers at once.

Ford, General Motors and Stellantis have rebuffed the UAW’s proposals as “unsustainable”. Ford claimed their last offer before the strike was “historically generous”.

“Ford remains absolutely committed to reaching an agreement that rewards our employees and protects Ford’s ability to invest in the future as we move through industry-wide transformation,” Ford said in a statement.

The union has emphasized the billions of dollars in profits the big three automakers have made since the 2008 economic recession and federal bailouts of the auto industry, where workers accepted numerous concessions that were never restored once the corporations returned to profitability.

The expanding strike is making political waves. President Joe Biden is facing pressure from Democratic colleagues to join workers on the picket line. Former president Donald Trump is set to hold a rally next week in Detroit with autoworkers during the Republican primary debate.

Biden has called on the automakers to increase their wage proposals to reach a deal with the UAW.

“I believe they should go further to ensure record corporate profits mean record contracts for the UAW,” Biden said last week.