FLINT, Mich - At midnight workers at the Flint GM assembly plant who are represented by the UAW walked off the job.
The union says 49,000 GM employees across the county are on strike.
The United Auto Workers union says its contract negotiations with General Motors have broken down and its roughly 49,000 members will go on strike just before midnight on Sunday.
The union's contract with GM expired Saturday night and union officials said the two sides were far apart on economic issues.
A United Auto Workers official says the union's General Motors workers will strike if the automaker "refuses to give even an inch" in contract negotiations.
UAW spokesman Brian Rothenberg says in a news release that such a strike would begin Sunday night.
The union let its contract with GM expire on Saturday, raising the possibility of a strike. UAW leaders are meeting Sunday in Detroit to discuss the union's next steps.
Union leaders have said the two sides are far apart on economic issues.
GM said in a statement Saturday night that it still held out hope for an agreement, saying it continues to work on solutions to difficult challenges.
The four-year contract between General Motors and the United Auto Workers expired Saturday, but workers were told to report to jobs as negotiations continued and the prospect of a national strike loomed.
The union let the contract lapse, raising the possibility of a strike as early as Sunday night.
There was a wrinkle. About 850 UAW-represented janitors with Aramark, a separate company, went on strike Sunday after working under an extended contract since March 2018.
The strike covered eight GM facilities in Ohio and Michigan. It appeared that GM workers were crossing picket lines Sunday set up by their own union. The Detroit Free Press reported that GM workers at a Flint, Michigan, truck plant reluctantly passed picketers.
GM said it has contingency plans for the Aramark strike.