(Bloomberg) -- President Joe Biden said he did not think a threatened strike by the United Auto Workers union against Detroit’s big three legacy carmakers would take place, as the two sides struggle to reach a new contract.

“I’m not worried about a strike. I don’t think it’s going to happen,” Biden told reporters after arriving in Philadelphia, where he will deliver a Labor Day address Monday.

The UAW’s 150,000 members are threatening a strike on General Motors Co., Ford Motor Co. and Stellantis NV, maker of the Jeep and Chrysler brands, if a deal is not reached by a Sept. 14 deadline. 

There are significant differences between the two sides over pay and benefits, and a transition to electric vehicles, which have raised concerns about a potential work stoppage after the current contract expires.

The Biden administration is pushing to move the US to electric vehicles, but union leaders worry thousands of jobs in EV battery plants for the big automakers aren’t union-protected. 

UAW President Shawn Fain met with Biden at the White House in July to update him on negotiations. Publicly, he has said Democrats need to do more to support the union’s fight for higher wages.

Biden previously had expressed concerns about the potential for a strike, urging automakers to avoid plant closings and to ensure that any necessary job transitions take place in the same factories and communities. 

In recent months, Biden has avoided other labor disputes that have threatened to upend supply chains, but the talks involving the UAW are the most fraught yet. 

The union endorsed Biden in 2020, but has yet to do so for his reelection bid.

Read More: What’s at Stake as US Auto Workers Threaten to Strike: QuickTake

©2023 Bloomberg L.P.