The union Communications Workers of America (CWA) filed a federal labor charge against Google Thursday, accusing the tech giant of unlawfully terminating employees in order to prevent them from participating in union activities.

The complaint states that Google fired four workers — Paul Duke, Laurence Berland, Sophie Waldman and Rebecca Rivers on Nov. 25 “to discourage and chill employees from engaging in protected concerted and union activities,” Reuters reports.

The filing will cause a National Labor Relations Board (NLRB) investigation into Google and whether the company violated the employees' right to voice collective concerns about working conditions.

A Google spokeswoman told The Hill in a statement: "We dismissed four individuals who were engaged in intentional and often repeated violations of our longstanding data security policies, including systematically accessing and disseminating other employees’ materials and work. No one has been dismissed for raising concerns or debating the company’s activities."

If NLRB investigation finds any wrongdoing by Google, CWA could seek a settlement or appeal the case to a court, according to Reuters.