Toyota Motor Corp has decided to end production at a California plant it has shared with General Motors for 25 years, industry sources said on Thursday.

Toyota's board met earlier in the day and decided to shut the plant in March, according to two sources, who had direct knowledge of the decision but were not authorized to speak on the record.

The Japanese automaker's operations at the Fremont, California, facility employ about 4,500 people.

A Toyota representative declined to comment on the reports, saying that the automaker expected to release a statement on the plant later on Thursday.

The plant has operated under a partnership with GM known as New United Motor Manufacturing Inc, or NUMMI. It had been a ground-breaking partnership that brought Toyota's lean manufacturing techniques to a U.S. workforce.

General Motors Co earlier decided to wind down production at the facility as part of its restructuring, which included bankruptcy proceedings. It cut operational ties to the plant in late June.

Earlier in August, Toyota President Akio Toyoda had said during his first appearance in the United States since taking the helm of the world's biggest automaker that a decision on the facility was expected shortly.

Toyota builds the Corolla compact car and the Tacoma pickup truck at the NUMMI plant, which has operated as a 50-50 joint venture with General Motors since 1984. It was not clear what plants would pick up the Corolla and Tacoma production.

GM, which had built the Pontiac Vibe at the plant until August 17, plans to wind down the Pontiac brand in its restructuring and left its stake in the joint venture with other assets to be liquidated in bankruptcy, in an entity known as Motors Liquidation Co.

California Gov. Arnold Schwarzenegger and state lawmakers had appealed to save the plant and its jobs. The NUMMI facility has the only Toyota workers represented by the United Auto Workers union.

California State Sen. Ellen Corbett said she had been working on a package of incentives aimed at keeping the plant open and was disappointed by Toyota's decision.

We will continue our efforts in the hope that there is any change of direction by Toyota and, if not, to work toward attracting another car manufacturer to the plant, Corbett said in a statement.

The UAW had urged members to contact U.S. lawmakers to try to convince Toyota to keep the plant open.

(Reporting by David Bailey and Soyoung Kim in Detroit, John Crawley in Washington, and Jim Christie in San Francisco, editing by Leslie Gevirtz, Gerald E. McCormick and Matthew Lewis)