Thousands of workers at General Motors could be laid off as the firm plans to close most of its factories in the US for up to nine weeks this summer, sources have said.
The closures are being blamed on a slump in sales and a growing inventory of unsold vehicles.
Analysts said sales could be declining at the company because of talk about a potential bankruptcy.
Workers would still get most of their pay because their United Auto Workers union contract requires the company to make up much of the difference between state unemployment benefits and their wages.
The exact dates and number of plants that face closures are not known, but it has been claimed they could occur in July, around the normal two-week shutdown, when changes are made from one model year to the next.
GM spokesman Chris Lee would only say the company notifies employees before making any production cuts public.
Reduced assembly line speeds could continue to run at a few plants where more popular models are made.
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