Microsoft Corp.’s planned $69 billion purchase of computer games developer Activision Blizzard Inc. faces an in-depth probe in the UK after regulators said the deal could hamper competition.

The Competition and Markets Authority said it decided to kickstart a longer review after Microsoft turned down the chance to offer remedies to address its concerns.

“Microsoft informed the CMA that it would not offer such undertakings,” the regulator said in its decision.

The move was expected after the CMA previously flagged concerns the deal could lead to a substantial lessening of competition in the gaming console, subscription, and cloud markets.

The regulator now has until March 1 to come to a final decision.

The combination with Activision — which owns some of the most popular franchises including Call of Duty, World of Warcraft, and Guitar Hero — will make Microsoft the world’s third-largest gaming company and boost the Xbox maker’s roster of titles for its Game Pass subscribers.

“We’re ready to work with the CMA on the next steps and address any of its concerns,” Brad Smith, Microsoft president, and vice chair said in a Sept. 1 statement.