DETROIT — The United Auto Workers union is challenging the results of last week’s organizing vote of Mercedes-Benz workers in Alabama, in which workers voted against union representation, and is asking federal officials to order a new election.

Among a dozen or so claims, the Detroit union alleges that the German automaker fired four pro-union workers, forced workers to attend anti-union meetings, and interfered with workers’ ability to advocate for the union.

Union organizing failed at the Alabama plant with 56% of the vote, or 2,642 workers, casting ballots against the UAW, according to the NLRB, which oversaw the election. More than 90% of the 5,075 eligible Mercedes-Benz workers voted in the election.

“All these workers ever wanted was a fair shot at having a voice on the job and a say in their working conditions,” the UAW said in a statement. “And that’s what we’re asking for here. Let’s get a vote at Mercedes in Alabama where the company isn’t allowed to fire people, isn’t allowed to intimidate people, and isn’t allowed to break the law and their own corporate code, and let the workers decide.”

The National Labor Relations Board confirmed Friday afternoon that its Atlanta-based office received the UAW’s objections to the election. Friday was the last day the union could file objections and challenge the election.

Mercedes-Benz in a statement Friday said company officials “worked with the NLRB to adhere to its guidelines and we will continue to do so” through the objection process. The automaker said it “sincerely hoped the UAW would respect our Team Members’ decision.”

The NLRB said its regional director will review the UAW’s allegations of an unfair election. If she finds that the objections raise substantial and material issues of fact that could be best resolved by a hearing, she will order a hearing. If after the hearing, she finds that the employer’s conduct affected the election, she can order a new election.

The agency also reconfirmed that it is processing and investigating unfair labor practice charges filed by the UAW against automakers, including six unfair labor practice charges against Mercedes-Benz since March.

After the results were announced, UAW President Shawn Fain accused the company of conducting an anti-union campaign, including “egregious illegal behavior,” but he declined to discuss the union’s potential plans to object to the results.

Fain said on May 17 that the union would continue to move forward with its charges against Mercedes-Benz, which allege that Mercedes-Benz has “disciplined employees for discussing unionization at work, prohibited distribution of union materials and paraphernalia, surveilled employees, discharged union supporters, forced employees to attend captive audience meetings, and made statements suggesting that union activity is futile,” the NLRB previously said.

The Alabama results were a blow to the UAW’s organizing efforts a month after it won an organizing drive of roughly 4,330 Volkswagen plant workers in Tennessee.

The Mercedes-Benz vote was expected to be more challenging for the union than the vote at the Volkswagen plant in Tennessee, where the union had already established a presence after two failed organizing drives in the past decade and where it faced less opposition from the automaker.