DETROIT (Reuters) -The United Auto Workers (UAW) said on Wednesday it won a vote to at a Ford joint-venture plant in Kentucky to unionize it, but believed 41 challenge ballots still pending to be illegitimate.

"We believe they are illegitimate and represent nothing more than an employer tactic to flood the unit and undermine the outcome," UAW said, urging Ford to acknowledge the "democratic decision" of its workforce.

The National Labor Relations Board and Ford did not respond to a request for comment outside regular business hours.