BERLIN (Reuters) - Mercedes-Benz on Wednesday said it recognises the right of its employees to form representatives after a U.S. auto workers union said it had filed complaints about the carmaker's "anti-union" campaign in its Alabama factory.

Factory workers at Mercedes-Benz U.S. International (MBUSI) assembly plant in Alabama are moving forward with efforts to join the United Auto Workers (UAW), and they plan to file a petition as soon as this week, a union leader said on Tuesday.

The UAW on Wednesday said it filed charges against Mercedes-Benz Group for violating Germany's global supply chain practices which prohibits German companies from disregarding workers' rights to form trade unions.

"Workers at Mercedes-Benz's sprawling assembly and battery plant in Vance, Ala., are organizing to join the UAW and have faced fierce backlash from company management," the union said in a statement.

UAW detailed its complaint detailed seven violations, such as firing a union supporter for using a cellphone at work for medical emergency and mandatory company events along with a letter from the CEO attempting to discourage workers from unionising.

The union said it had also filed multiple charges with the U.S. National Labor Relations Board (NLRB).

A spokesperson for Mercedes-Benz said the company had not received a complaint in Germany and therefore could not comment further.

"At the Mercedes-Benz Group we recognise the right of our employees to form employee representatives," the spokesperson said, adding that the union's allegations regarding the union supporter were inaccurate.

The carmaker said its subsidiary management wanted to ensure its team members can make an informed decision after the union's the national campaign to increase membership, adding that carmaker will present its side of the matter to the U.S. authorities.