Tens of thousands of General Motors workers in the U.S. have been called out on strike after GM and the United Auto Workers union failed to reach a new pay and conditions deal.

BBC reports that the previous four-year contract between the UAW and GM expired this weekend. The two had held negotiations in a host of issues including wages, healthcare, profit sharing, and job security but a compromise couldn’t be reached. The union is also fighting GM to stop closing car assembly plants in Ohio and Michigan and on Sunday at 11:59 p.m., a total of 46,000 workers from GM walked off the job.

“We do not take this lightly. This is our last resort,” UAW vice-president Terry Dittes said of the strikes. “We are standing up for fair wages, we are standing up for affordable, quality health care. We are standing up for our share of the profits.”

Also Read: UAW Workers Could Walk Off The Job At GM This Weekend As Contract Deadline Looms

A statement issued by GM revealed that it had offered the workers union more than $7 billion in new investments, 5400 more jobs, and various pay and benefits increases.

“We presented a strong offer that improves wages, benefits and grows U.S. jobs in substantive ways and it is disappointing that the UAW leadership has chosen to strike at midnight tonight,” GM wrote. “We have negotiated in good faith and with a sense of urgency. Our goal remains to build a strong future for our employees and our business.”

A previous strike of GM’s employees in the United States back in 2007 lasted two days and cost the company $300 million.