Uber Technologies Inc.’s offices in Amsterdam were raided for the third time this year as Dutch authorities continued a criminal probe into the company’s UberPop ride-sharing service.

Uber continues to offer UberPop in four Dutch cities, despite already being fined 450,000 euros ($505,000) for the service, the public prosecutor said on its website Tuesday. The authorities believe the service violates national transport laws that prohibit organized taxi services without licensed drivers.

“They are suspected of offering taxi services without a permit in an organized way,” Marieke van der Molen, a spokeswoman for the public prosecutor, said by phone.

Legal and political challenges have piled up for San Francisco-based Uber in Europe. The company has suspended UberPop in France after a string of difficulties in the country, including clashes with taxi drivers, tensions with the government and arrests of top executives. A French court confirmed the ban on UberPop Sept. 22, according to Agence France-Presse, while the service has also been banned halted in Germany and Belgium. In Amsterdam, Uber drivers this year reported being threatened by masked men.

Documents were seized Tuesday and will be studied before proceeding with a criminal lawsuit, Van der Molen said. Uber’s office in the Dutch capital was raided in March and an employee was arrested in April for refusing to cooperate in a second raid, the prosecutor said at the time.

An Uber spokesman in Amsterdam confirmed Tuesday’s raid, declining to give further details.

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