The Federal Trade Commission on Thursday sued to block Microsoft’s $69 billion acquisition of Activision Blizzard, challenging one of the largest tech acquisitions in history.

The administrative complaint filed Thursday by the FTC alleges that the blockbuster deal, which would make Microsoft the third-largest video game publisher in the world, would give Microsoft “both the means and motive to harm competition” — claiming it could negatively affect prices of video games as well as game quality and player experiences on consoles and gaming services, according to an agency release.

“We continue to believe that this deal will expand competition and create more opportunities for gamers and game developers,” Brad Smith, Microsoft’s president, said in a statement Thursday. “We have been committed since Day One to addressing competition concerns, including by offering earlier this week proposed concessions to the FTC. 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.”