Microsoft is likely to receive an EU antitrust warning about its $69 billion bid for "Call of Duty" maker Activision Blizzard, people familiar with the matter said, that could pose another challenge to completing the deal.

The European Commission is readying a charge sheet known as a statement of objections setting out its concerns about the deal which will be sent to Microsoft in the coming weeks, the people said.

The EU antitrust watchdog, which has set an April 11 deadline for its decision on the deal, declined to comment.

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Microsoft said: "We're continuing to work with the European Commission to address any marketplace concerns. Our goal is to bring more games to more people, and this deal will further that goal."

The US software giant and Xbox maker announced the acquisition in January last year to help it compete better with leaders Tencent and Sony.

US and UK regulators, however, have voiced concerns, with the US Federal Trade Commission going to court to block the deal.

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Microsoft was expected to offer remedies to EU regulators in an attempt to avert a statement of charge and shorten the regulatory process, other sources familiar with the matter told Reuters in November.

The EU competition enforcer, however, is not expected to be open to remedies without first sending out its charge sheet, although there are ongoing informal discussions on concessions, the people said.

Microsoft last month reached a 10-year deal with Nintendo to make "Call of Duty" available on Nintendo consoles, saying it was open to a similar agreement with Sony, which is critical of the acquisition.

The deal has received the green light without conditions in Brazil, Saudi Arabia and Serbia.

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