Next week's Democratic debate is now in jeopardy after all seven candidates slated to participate said they will refuse to take the stage over a labor strike at the proposed venue -- chaos that comes after the location was already moved once.

Massachusetts Sen. Elizabeth Warren, Vermont Sen. Bernie Sanders, entrepreneur Andrew Yang, former Vice President Joe Biden, environmentalist Tom Steyer, South Bend, Ind. Mayor Pete Buttigieg and Minnesota Sen. Amy Klobuchar all announced in rapid succession Friday afternoon their plans to sit out the Thursday debate at Loyola Marymount University (LMU) if the college's food service workers are picketing.

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"I stand with them," Warren tweeted Friday. "The DNC [Democratic National Committee] should find a solution that lives up to our party's commitment to fight for working people. I will not cross the union's picket line even if it means missing the debate."

Sanders immediately followed with his own tweet in support of the workers of Unite Here Local 11, a labor union representing the hospitality and food service workers at the university.

A Sanders campaign spokesperson told Fox News that if the labor dispute isn't resolved and there isn't an alternative venue, Sanders will skip the Los Angeles debate, which will be co-hosted by PBS NewsHour and Politico.

"He's not going to cross the picket line. Simple as that," the campaign spokesperson said.

The Democratic National Committee only learned of the issue earlier Friday and said they are working on a resolution.

“While LMU is not a party to the negotiations between Sodexo and Unite Here Local 11, Tom Perez would absolutely not cross a picket line and would never expect our candidates to either,” DNC Communications Director Xochitl Hinojosa said. “We are working with all stakeholders to find an acceptable resolution that meets their needs and is consistent with our values and will enable us to proceed as scheduled with next week’s debate."

The debate was initially scheduled to be held at the University of California, Los Angeles, but the DNC canceled the location on Nov. 6 over ongoing labor disputes between the university and AFSCME Local 3299. LMU was picked as the alternative site.

Local 11 announced Friday it would protest the debate's second site because contract negotiations have stalled between the union and Sodexo, which runs food operations for students and employees at LMU's campus. About 150 dishwashers, cashiers, cooks and servers are affected by the union dispute.

“We had hoped that workers would have a contract with wages and affordable health insurance before the debate next week. Instead, workers will be picketing when the candidates come to campus,” Susan Minato, the co-president of UNITE HERE Local 11, said in a statement.

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A union rep told Fox News the foodservice employees had been working without a contract for several weeks and had already held several pickets in an attempt to earn better wages, benefits and working conditions.

The employees were planning to work as normal on debate day, but didn't rule out the possibility of a work stoppage, the union spokesperson said.

A source familiar with the matter said the DNC and LMU were not made aware of the planned picket until after the union sent a letter to the candidates Friday.

A Sodexo spokesperson told Fox News they are searching for a solution.

"Sodexo is 100 percent committed to reaching an agreement, and any statement that we have left the bargaining table is not accurate," the spokesperson said. "We have been negotiating in good faith with the Unite Here Local 11 since December of last year with a goal to reach a new collective bargaining agreement that is equitable for everyone, including our employees, and we still intend to achieve such an agreement.”

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It's unclear whether the DNC could move the debate location again in such short notice with the avalanche of candidates threatening to bow out.

"We must live our values and there is nothing more core to the Democratic Party than the fight for the working people," Yang tweeted.

"We’ve got to stand together with @UniteHere11 for affordable health care and fair wages," Biden said. "A job is about more than just a paycheck. It's about dignity."

Steyer tweeted: "I support @UNITEHERE11. If their dispute with @sodexoUSA is not resolved before the debate, I will not cross the picket line. I trust the DNC will find a solution ahead of the debate, and I stand with @LoyolaMarymount workers in their fight for fair wages and benefits."

"I stand in solidarity with the workers of @UNITEHERE11 at Loyola Marymount University and I will not cross their picket line," Buttigieg said.

"As I said at my event with labor leaders here in Miami, I will not cross the picket line and I will stand with @UniteHere11 to fight for the dignity of work," Klobuchar tweeted.

LMU released a statement Friday distancing the university from the Sodexo-union dispute and encouraging the two sides to talk in advance of the debate.

“LMU is not a party to the negotiations between Sodexo and Unite Here Local 11,” the statement said. “The university has encouraged and continues to encourage Sodexo to resolve issues raised by Local 11. Earlier today, LMU asked Sodexo to meet with Local 11 next week to advance negotiations and solutions.”

The university added: “LMU is not an agent nor a joint employer of Sodexo, nor of the Sodexo employees assigned to our campus. LMU is proud to host the DNC Presidential Debate and is committed to ensuring that the university is a rewarding place to learn, live, and work.”

Fox News' Andrew Craft, Lee Ross and Tara Prindiville contributed to this report.