DETROIT/WASHINGTON (Reuters) - Workers at a Mercedes Benz factory in Vance, Alabama, filed a petition with U.S. regulators to hold an election to join the United Auto Workers, the union said on Friday.

The SUV plant is the second to file an election petition with the National Labor Relations Board (NLRB) in recent weeks. Reuters previously reported that Mercedes workers in Alabama would file an election petition with the NLRB as soon as this week.

The UAW said a "supermajority" of the more than 5,000 eligible Mercedes workers at the plant signed cards to join the union. The UAW hopes for a vote by early May.

The elections come after months of organizing efforts at more than a dozen non-union automakers owned by foreign companies like Hyundai Motor ( HYMTF ) and Toyota Motor ( TM ), as well as EV makers like Tesla and Rivian.

After securing record contracts for the Detroit Three - General Motors ( GM ), Ford and Stellantis ( STLA ) - UAW President Shawn Fain pledged to accomplish a goal the labor group has failed at repeatedly over the last few decades: welcoming a new automaker to its unionized ranks.

The UAW's latest efforts come at a time when it has an ally in the White House. President Joe Biden, who last fall joined a UAW picket line in Michigan - a key battleground state in this fall's election - has backed UAW efforts to organize the nonunion automakers.

In Chattanooga, Tennessee, workers at a Volkswagen plant were first to petition for a UAW vote, which is expected to be finalized by April 19. UAW organizers have twice lost a vote at that plant, narrowly missing a majority in 2014 and 2019. There have also been failed attempts at plants owned by Japanese automaker Nissan ( NSANF ).

Union officials have claimed in filings to federal regulators that some automakers are retaliating against workers or encumbering their attempts to organize. The labor group on Wednesday filed charges against Mercedes for violating Germany's new law on global supply chain practices, which prohibits German companies from disregarding workers' rights to form trade unions.

The company responded to some of the union's charges, saying they are inaccurate. It also said the company recognizes its employees' rights to organize.