The US Federal Trade Commission is trying to temporarily block the deal between Microsoft and Activision Blizzard in court, reports CNBC.

The Federal Trade Commission on Monday applied for a temporary restraining order and preliminary injunction seeking to block Microsoft’s acquisition of Activision Blizzard before the deal’s July 18 deadline.

The commission fears that if Microsoft is allowed to buy Activision, Microsoft will have the ability to “withhold or degrade” Activision’s gaming products at the expense of price, game quality, experience with competitors’ offerings, or “withholding content from competitors entirely.”

In other words, the trade commission is concerned that Microsoft could prevent popular games from Activision Blizzard’s library from running on other game consoles, such as those sold by Sony. Or it may charge more for games that come out on other consoles.

Call of Duty is one such game. And while it’s now available on all platforms, and Microsoft has promised to continue to sell the series widely, there are fears that the tech giant may have the power to “hold” these or similar games to Xbox, taking buyers away from Sony and other console makers.

We will remind that in May the European Commission approved the proposed Microsoft acquisition of Activision Blizzard. This came shortly after the Competition and Markets Authority (CMA), the UK’s antitrust regulator, blocked the deal.