Jeep maker Stellantis reached a tentative contract agreement with the United Auto Workers union on Saturday as it escalated strikes against General Motors by adding a plant in Tennessee.

The Stellantis deal, which still must be ratified by members, leaves only GM without an agreement with the union. But the union walked out Saturday night at a GM factory in Spring Hill, Tennessee, in an effort to increase pressure on the company to reach a deal.

The Stellantis deal mirrors one reached earlier this week with Ford. The union says the contract also saves jobs at a factory in Belvidere, Illinois, that Stellantis had planned to close.

GM said it was disappointed with the additional strike at the Spring Hill assembly and propulsion systems plant “in light of the progress we have made.” The company said in a statement that is has bargained in good faith with the union and wants to reach a deal as soon as possible.