The United Auto Workers union and Ford have reached a tentative deal on a new contract on Wednesday, nearly six weeks after the union embarked on an unprecedented strike against all of the Big Three automakers.

The agreement with Ford still needs to be reviewed by the UAW leadership at Ford, and then it would need to be ratified by a majority of union members at the automaker.

But UAW President Shawn Fain called it a "historic agreement" in a post on X, formerly known as Twitter.

In a statement, Fain also said the union had won major concessions.

"We won things nobody thought possible," said Fain in a statement. "Since the strike began, Ford put 50% more on the table than when we walked out. This agreement sets us on a new path to make things right at Ford, at the Big Three, and across the auto industry."

According to the UAW, the deal includes wage increases of 25% over four-and-a-half years and the return of a cost of living adjustment.

Included as well in the tentative deal is a three-year progression for full-time employees to the top wage, improvement to retirement benefits, and the right to strike over plant closures, which would mark a first for the union.

Pressure is now on for GM and Stellantis

The deal is likely to ramp up pressure on GM and Stellantis to also reach tentative deals after the UAW this week expanded its strike at the largest plants of each of the automakers, where many of their bestselling trucks and SUVs are built.

The UAW justified the expansion by saying they were not making enough progress in contract talks with the two automakers.

The deal with Ford is not yet a done deal, however.

Workers at Ford could choose to send their negotiators back to the table to push for more.

UAW-represented workers at Mack Trucks did that earlier this month after negotiators had reached a tentative deal. And in 2021, union workers at John Deere rejected two tentative agreements before finally approving a more lucrative contract.

For now, rougly 16,600 employees at Ford's Kentucky Truck Plant, Chicago Assembly Plant and Michigan Assembly will return to work.

In addition, more than 3,000 workers laid off by Ford in what the company called a ripple effect of the strike are also expected to be back on the job.

That leaves about 28,000 autoworkers at General Motors and Stellantis, who the UAW says will remain on strike.

"We are working constructively with the UAW to reach a tentative agreement as soon as possible," GM said in a statement after the deal was announced.

President Biden, who paid a visit to striking autoworkers in Michigan last month, applauded the deal.

"It's showing how collective bargaining works by providing workers a seat at the table and the opportunity to improve their lives while contributing fully to their employer's success," Biden said in a statement.