DETROIT, MI—Source: United Auto Workers threaten to expand targeted strike if there is no substantive progress by Friday

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

In a video statement late Monday, UAW President Shawn Fain said workers at more factories will join those on the fifth day of a strike at three plants. Ford, General Motors, and Stellantis said they wanted to settle the strike and 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.

A Ford spokeswoman said Tuesday that negotiations continued but provided no additional details. 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 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, indicating 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 another union, the United Steelworkers. However, The company said, “We do not believe that many will be impacted,” and that production will be shifted to other U.S. plants.

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.

President Joe Biden said he would send two top administration officials, including acting Labor Secretary Julie Su, to Detroit this week to meet with both sides. Biden has publicly backed the UAW, saying workers deserve to share in the automakers’ recent record profits.

The UAW has pointed to those profits, which the companies recorded as prices rose sharply on strong consumer demand and a limited supply of vehicles because of chip shortages and other issues. The union is seeking wage increases of more than 30% over four years and other sweeteners.

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

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