The leader of the United Auto Workers said that a strike currently targeting plants in Missouri, Michigan and Ohio may be expanded if “serious progress” toward a new contract agreement isn't made by noon Friday.

The UAW is striking all three Detroit automakers for the first time in its history, but the 13,000 workers on the picket lines have focused on three facilities, one each from GM, Ford and Stellantis. The union can stretch the funds it maintains for striking autoworkers if it limits picketing, but targeted strikes can still ripple through integrated production systems.

The previous contracts with the Detroit 3 auto companies ended 11:59 pm Sept. 14.

In a video statement late Monday, UAW President Shawn Fain said more factories may be picketed if there is no significant progress in talks by the end of the week.

Stellantis resumed negotiations with the UAW this week and on Tuesday, the company's North American Chief Operating Officer Mart Stewart said common ground is still being sought to end the standoff.

A spokesman for General Motors said representatives of the company and the United Auto Workers also were continuing to negotiate.

The union's strategy hinges on its ability to escalate the strike quickly, and the carmakers are warning of potential layoffs as the limited strike reduces the amount of material needed at plants that remain open.

GM said Monday that 2,000 UAW-represented workers at an assembly plant in Kansas City are “expected to be idled as soon as early this week" because of a shortage of supplies from a GM plant near St. Louis, where workers walked off the job Friday. The strike also could begin to affect suppliers and their employees too. 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.

In a sign of concern of the strike's potential economic and political fallout, the Biden administration stepped up its response.

President Joe Biden is sending two top administration officials to Detroit to meet with both sides. Biden has backed the UAW in brief public comments, saying that the automakers have not fairly shared their record profits with workers.

Copyright 2023 NEWSnet and The Associated Press. All rights reserved.