(Reuters) -The U.S. Federal Trade Commission (FTC) is likely to file an antitrust lawsuit to block Microsoft Corp's $69 billion takeover bid for video game publisher Activision Blizzard Inc, Politico reported on Wednesday.

A lawsuit challenging the deal is not guaranteed, and the FTC's four commissioners have yet to vote out a complaint or meet with lawyers for the companies, the report said, citing two of the three people with knowledge of the matter.

However, the FTC staff reviewing the deal are skeptical of the companies' arguments, the report said.

Shares of Activision fell about 2% in extended trading after closing 1% higher.

Microsoft said in January it would buy Activision, the maker of "Call of Duty" and "Candy Crush" games, in the biggest gaming industry deal in history as global technology giants staked their claims to a virtual future.

"We are committed to continuing to work cooperatively with regulators around the globe to allow the transaction to proceed, but won't hesitate to fight to defend the transaction if required," an Activision Blizzard spokesperson said, adding any suggestion that the transaction could lead to anticompetitive effects is "completely absurd".

The FTC and Microsoft did not immediately respond to requests for comment from Reuters.

The proposed bid is also facing EU scrutiny as regulators opened a full-scale investigation earlier this month and warned about the impact of the deal.

(Reporting by Tiyashi Datta in Bengaluru; Editing by Sriraj Kalluvila)