NASHVILLE (AP) - A signed agreement shows that Volkswagen officials reneged on a pledge to recognize the United Auto Workers without another vote at the German automaker's lone U.S. plant in Tennessee, a top union official said Tuesday.

Gary Casteel, the UAW's secretary-treasurer, released the 2014 document stating that Volkswagen would recognize the UAW as the representative of its members in exchange for the union dropping a challenge to the outcome of a union election at the plant in Chattanooga.

"Volkswagen never fulfilled its commitments to recognize the union as a representative of its members," Castell said in a conference call. "The unfulfilled commitment is at the heart of the ongoing disagreement between the company and the union."

The union said the written agreement for the company to "recognize the UAW as a 'members union'" stemmed from negotiations led by Volkswagen's then-chief financial officer, Hans Dieter Poetsch, wh o has since been named chairman amid the company's diesel emissions cheating scandal.

But Volkswagen Chattanooga spokesman Scott Wilson countered in an email that the company has "no contract with the UAW." He said the agreement is reflected in a labor policy established at the plant to formalize meetings between worker representatives and management, but stops well short of collective bargaining.

That arrangement "remains an excellent way for deepening the dialogue with employee organizations," Wilson said.

Casteel told reporters that plant-specific labor policy is "by no stretch" what the negotiators envisioned.

"We all talked extensively about what recognition means and what would occur if we withdrew our objections to the election," he said. "The meaning was very clear to all in the room."

Republican politicians in Tennessee and across the region have long opposed the United Auto Workers gaining a foothold among foreign owned plants. And befo re the 2014 union vote at the plant, Republicans in the state Legislature warned that state grants and incentives to expand the plant could be lost if the UAW won.

Following the union's 712-626 defeat in the 2014 vote, the UAW mounted a legal challenge on the basis that the election was tainted by unfounded fears sown by labor opponents.

The union dropped the case after reaching its agreement with the company. Workers specializing in the maintenance of machinery and robots at the Chattanooga factory in December voted 108-44 in favor of UAW representation.

But the company refused to enter into a collective bargaining with the skilled-trades workers, arguing that that only the entire blue-collar workforce at the plant should be allowed to make labor decisions there.

The National Labor Relations Board has ruled in the UAW's favor on allowing the smaller group of workers to seek union representation. But Volkswagen has vowed to challenge that decision in federal appeals court.

The union agreement with the company was released on the eve of Volkswagen's shareholder meeting Wednesday, where UAW supporters plan to hand out fliers highlighting the labor dispute in the U.S.

It also comes as German prosecutors have launched an investigation into former CEO Martin Winterkorn and another unnamed executive over allegations they didn't inform investors soon enough about the company's scandal over cars rigged to cheat on U.S. diesel emissions tests.

Casteel drew parallels between the emissions scandal and the company's labor policies, saying that a "common thread is a disregard for its corporate commitment and in our case a disregard for U.S. law."

"We believe the company is better than this," he said.