The United Auto Workers union and Ford have agreed in principle to the terms of a tentative agreement that could signal the end to the nearly six-week strike with the Big Three automaker, sources with knowledge of the discussions confirmed Wednesday to CNBC.

A tentative agreement could be announced as early as Wednesday night, pending approval of UAW leaders, according to two sources, who agreed to speak on the condition of anonymity because of the sensitive nature of the talks.

The agreement will need to be ratified by UAW members, thousands of whom have walked off the job at Ford factories throughout the U.S., including its Kentucky Truck Plant, the company’s largest factory worldwide.

United Auto Workers President Shawn Fain after a rally for striking workers at UAW Local 551 in Chicago on Oct. 7.John J. Kim / Chicago Tribune via Getty Images file

The automaker and the union participated in intense bargaining Tuesday and Wednesday in an attempt to finalize a record deal, the sources said.

Spokespeople for Ford declined to comment to CNBC on the negotiations earlier Wednesday other than to say talks were continuing. A UAW spokesman did not respond to CNBC’s request for comment.

The talks this week involved a proposal for wage increases of at least 25% over the term of the deal, as well as other improved benefits previously outlined by the union and company, two sources confirmed to CNBC.

Around 13,000 UAW members went on strike Sept. 15 in an action that hit Ford, General Motors and Stellantis at the same time. The union had never engaged in a simultaneous strike against all three companies.

The UAW gradually ramped up those strikes in subsequent weeks, and as of Wednesday, about 40,000 people had walked off the job. That slowly cut into vehicle production and supply lines.

In mid-October, the union told workers to strike at plants where highly profitable vehicles like full-size SUVs and trucks were made. They were Kentucky Truck, a Stellantis facility in Sterling Heights, Michigan; and a GM plant in Arlington, Texas.

The UAW said those three were the largest manufacturing plant owned by each company.

GM said days ago that the strikes were costing it about $200 million a week.

In another historic first, President Joe Biden became the first sitting president to walk a picket line when he visited UAW workers in Belleville, Michigan.