DETROIT (AP) — The United Auto Workers union said Wednesday it has reached a tentative contract agreement with Ford that could be a breakthrough toward ending the nearly 6-week-old strikes against Detroit automakers.

The four-year deal, which still has to be approved by 57,000 union members at the company, could bring a close to the union’s series of strikes at targeted factories run by Ford, General Motors and Jeep maker Stellantis.

The Ford deal could set the pattern for agreements with the other two automakers, although no other agreements were announced.

The United Auto Workers union is expected to announce a tentative contract agreement with Ford Wednesday night that could be a breakthrough toward ending the nearly 6-week-old strikes against Detroit automakers.

Two people with knowledge of the bargaining said the company and union are working on the final details of the contract and could announce it Wednesday evening in a video appearance with UAW President Shawn Fain. The people asked not to be identified because they’re not authorized to speak publicly about the bargaining.

Terms of the deal weren’t immediately available, but both sides have been discussing a four-year contract. It would have to be approved by 57,000 union members at Ford.

The progress in the negotiations came after the union this week walked out at three factories that produce highly profitable pickup trucks and SUVs, adding them to the list of plants already on strike in a strategy to intensify pressure on the companies.

On Tuesday, about 5,000 workers at GM’s assembly plant in Arlington, Texas, walked out, halting production of truck-based SUVs that are huge profit makers for the company. A day earlier, the UAW’s president, Shawn Fain, had added 6,800 employees at Stellantis’ Ram pickup plant in Sterling Heights, Michigan.

Two weeks ago the union struck Ford’s largest and most profitable factory, the Kentucky Truck Plant in Louisville, where 8,700 workers make heavy-duty F-Series pickups and two large SUVs.

In all, about 46,000 workers have walked out at factories owned by the three companies in a series of targeted strikes that began Sept. 15. About 32% of the union’s 146,000 members at the automakers are now on strike and getting by on $500 per week in strike pay. The automakers have been laying off workers at other plants as parts shortages have cascaded through their manufacturing systems.

Todd Dunn, president of the UAW local at Ford’s Kentucky Truck Plant, said he was told by people within the union’s leadership that the company is nearing an agreement.

“I’ve heard they are moving the needle as aggressively as possible,” Dunn said in an interview Wednesday. “It’s very positive.”