Britain on Thursday announced an "in-depth investigation" into Microsoft's planned $69-billion takeover of US gaming giant Activision Blizzard, citing UK competition concerns.
US technology giant Microsoft in January announced a bid to create the world's third biggest gaming company by revenue, behind China's Tencent and Japan's Sony, by purchasing the owner of hit games "Candy Crush" and "Call Of Duty".
The proposed deal, already controversial owing to allegations of sexual harassment against women at Activision, now faces a probe by Britain's Competition and Markets Authority.
"The CMA has referred the anticipated acquisition by Microsoft Corporation of Activision Blizzard, Inc. for an in-depth investigation," a statement said.
It added that the "merger may be expected to result in a substantial lessening of competition within a market or markets in the United Kingdom".
Activision Blizzard's portfolio also includes the popular game "World Of Warcraft".
Sorcha O'Carroll, senior director of mergers at the CMA, previously expressed concern that Microsoft could use its control over Call Of Duty and World Of Warcraft "to harm rivals, including recent and future rivals in multi-game subscription services and cloud gaming".
Sony has expressed concerns that Call of Duty might no longer be accessible on its PlayStation console.
Microsoft dismissed such a suggestion, however, saying in a statement Thursday that "it makes zero business sense... to remove Call of Duty from PlayStation given its market leading console position".