About 49,000 General Motors employees walked off the job at midnight Sunday after negotiations between the United Automobile Workers union and the Detroit-based carmaker broke down. The union had announced plans for the nationwide strike Sunday afternoon, and no deal was reached before the midnight deadline. It is the first national UAW strike since 2007.

The collective bargaining agreement expired Saturday at midnight. Despite ongoing talks since July, when the union met with GM leadership to renew an arrangement in place since 2015, the parties remain divided on several key issues. The UAW said it is aiming to secure fair wages, affordable health care and better job security, among other things.

"We stood up for General Motors when they needed us most," said UAW Vice President Terry Dittes in a statement Sunday. "Now we are standing together in unity and solidarity for our members, their families and the communities where we work and live."

In a statement, GM said it offered to create more than 5,400 jobs, add more than $7 billion in investments and implement improved plans for profit-sharing and health benefits.

"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," the news release Sunday read. "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."

The strike was greenlit Sunday in Detroit during a UAW meeting of nearly 200 regional leaders gathered from at least seven states. The group voted unanimously in favor of the plan, union spokesman Brian Rothenberg told The Washington Post.

For every auto assembler, there are several manufacturing and supply workers outside GM that could be adversely affected if the plants shut down, Rothenberg said Sunday. "But this is a sacrifice worth making. It's not just standing up for ourselves. It's standing up for all of us."

If the strike commences, more than a thousand Teamsters will refuse to transport GM vehicles to dealerships in a move of solidarity with UAW, said Bret Caldwell, a spokesman for the International Brotherhood of Teamsters.

"Our members won't cross the picket line," Caldwell said Sunday. "They stood with us when we have fought employers. This is another way we can stand with them."