The United States government has filed a lawsuit attempting to stop Microsoft from buying Activision, the creators of the popular video game “Call of Duty.”

In a lawsuit filed by the Federal Trade Commission (FTC), regulators sought to halt the $68.7 billion sale of Activision to Microsoft. Holly Vedova, the director of the FTC, said, “Microsoft has already shown that it can and will withhold content from its gaming rivals. Today, we seek to stop Microsoft from gaining control over a leading independent game studio and using it to harm competition in multiple dynamic and fast-growing gaming markets.”

According to court documents, the FTC argued that Microsoft could take popular games under Activision’s brand and make them unplayable on other competitors’ devices, including computers, gaming consoles, and mobile devices. Activision, one of the world’s biggest gaming companies in the United States, is behind multiple popular games, including World of Warcraft, Diablo, Call of Duty, and Overwatch. Microsoft’s competitors have also voiced concern over the potential purchase, with Sony and Tencent saying the deal would give Microsoft too much control.

Despite the concern, Microsoft vowed to push forward with the deal and says they will mount an aggressive case to defend their intended purchase of Activision. In a statement, Microsoft President Brad Smith said, “While we believed in giving peace a chance, we have complete confidence in our case and welcome the opportunity to present our case in court.” Microsoft has previously argued that its purchase of Activision would help them compete with other gaming companies in the United States.