The United Auto Workers union is stepping up pressure on Detroit’s Big Three by threatening to expand its strike unless it sees major progress in contract negotiations by Friday.

In a video statement late Monday, UAW President Shawn Fain said workers at more factories will join those who are now in the fifth day of a strike at three plants.

“We’re not going to keep waiting around forever while they drag this out … and we’re not messing around,” Fain said in announcing the noon Eastern time Friday deadline for escalating the strike unless there is “serious progress” in the talks.

Ford, General Motors and Stellantis said they want to settle the strike, and they held back from directly criticizing the escalation threat.

Mark Stewart, the North American chief operating officer of Stellantis, the successor to Fiat Chrysler, said the company is still looking for common ground with the UAW.

“I hope that we’re able to do that by Friday,” Stewart said on CNBC.

GM said in a statement, “We’re continuing to bargain in good faith with the union to reach an agreement as quickly as possible for the benefit of our team members, customers, suppliers and communities across the U.S.”

A Ford spokeswoman said Tuesday that negotiations were continuing, but provided no additional details.

In Washington, the Biden administration reversed a plan to send acting Labor Secretary Julie Su and senior adviser Gene Sperling to Detroit this week to meet with both sides, according to a White House official. Last week, President Joe Biden publicly backed the UAW and said the officials could play a positive role.

The White House now believes that since negotiations are taking place, “it is most productive for Sperling and Su to continue their discussions from Washington and allow talks to move forward,” said the official, who spoke on condition of anonymity to discuss the private plans.

Fain had discounted the need for help from Washington, saying “This battle is not about the president,” and some Democrats opposed the White House involvement.

“I do not believe that the president himself should intervene as he did in the railroad strike in these talks. He should not be at that table,” said Rep. Debbie Dingell, whose congressional district includes part of southeast Michigan.

So far the strike is limited to about 13,000 workers at a Ford assembly plant in Wayne, Michigan, a GM factory in Wentzville, Missouri, and a Stellantis plant in Toledo, Ohio.

However, the carmakers have warned that there could be layoffs at other locations as the strike crimps the industry’s supply chain.

GM warned Monday that the strike in Wentzville, near St. Louis, could force the company to idle an assembly plant in Kansas City early this week. On Tuesday, the company said that it expected to keep production going in Kansas City for at least one more day.

The strike could soon begin to affect suppliers to the Big Three.

United States Steel Corp. said it was temporarily idling one of its blast furnaces in Granite City, Illinois, an indication that the company expects the strike to reduce demand for steel. There are about 1,450 workers at the site — most of them represented by the United Steelworkers, but the company said many workers won’t be affected by the furnace shutdown.

The area’s congresswoman, Democrat Nikki Budzinski, said U.S. Steel was using the strike as an excuse to idle the furnace. “Their effort to blame this announcement on the United Auto Workers strike is a shameful attempt to pit working people against one another,” she said.

A parts supplier, CIE Newcor, told Michigan officials that it expects a one-month closure of four plants in the state to start Oct. 2 and idle nearly 300 workers.

Jose Munoz, president and chief operating officer of South Korean car maker Hyundai Motor Corp., told reporters Tuesday in Atlanta that auto-parts makers would be disrupted by a long strike. Those problems could hurt production at nonunion automakers, not just the Big Three, he said.

“The way the supply chain works today, everything is interconnected,” Munoz said. “It is very difficult to have one supplier that is working only with one (auto manufacturer). So in a way or another, we will see disruptions in the supply chain which may impact companies over time.”

The UAW is seeking wage increases of more than 30% over four years and other sweeteners. The union says workers deserve a bigger share of record profits that the companies posted as prices rose sharply on strong consumer demand and a limited supply of vehicles because of chip shortages and other issues.

The companies say they can’t afford to meet the UAW’s demands because they must invest those profits to help them make the transition to electric vehicles.

Unifor, the union that represents Canadian autoworkers, extended talks with Ford Motor Co. by 24 hours early Tuesday after receiving a “substantive offer” on a new labor contract just as the current agreement expired.

(AP)