Microsoft could face a roadblock in its attempt to take over game maker Activision Blizzard due to a UK regulator, according to a new report. The UK’s Competition and Markets Authority (CMA) has reportedly expressed concerns that the the Redmond company’s $69 billion (roughly Rs. 5,49,900 crore) deal to acquire the firm could negatively affect rivals who offer access to the publisher’s titles, while limiting their ability to compete in the cloud gaming sector. The firms reportedly have less than a week to propose ways to address the CMA’s concerns.

 According to a report by the Associated Press, the CMA on Thursday expressed its concerns in connection with Microsoft’s attempt to acquire Activision Blizzard, which was first revealed in January. The UK regulator is not the first to voice concerns regarding the deal — the FTC announced in February that it would review Microsoft’s deal with the game publisher.

Microsoft is “ready to work with the CMA on next steps and address any of its concerns,” the company’s president Brad Smith said, according to the report.

One of the concerns raised by the CMA was that Microsoft’s deal could affect rivals that offered access to Activision Blizzard games, according to the report. The firm is known for several popular titles and gaming franchises, including Call of Duty, World of Warcraft, Overwatch, and Diablo.

As per the report, the UK regulator has also expressed concerns regarding the impact of the deal on competition in the upcoming cloud gaming sector.

The CMA, which opened an initial inquiry into the deal in July, has reportedly asked Microsoft and Activision Blizzard to respond to its concerns within five days, before the deal faces further scrutiny.