A US court on Tuesday banned Microsoft from completing the purchase of Activision Blizzard, one of the world's largest video game companies, until the court rules on an appeal brought by the competition authority.

The decision, made by the federal court in San Francisco, comes in response to a request filed on Monday by the US Federal Trade Commission (FTC).

The FTC, the US competition authority, had asked for the temporary suspension of the acquisition, valued at 69 billion dollars, claiming that Microsoft was trying to close the deal before the trial began.

Something that would be "difficult, if not impossible" to reverse if the acquisition was later found to be illegal, the commission said.

Thus, the court said that the order to temporarily block the deal "is necessary to maintain the 'status quo'" while the FTC's legal proceedings against the transaction are still pending.

Meanwhile, the court has scheduled a hearing for June 22 on another request by the FTC for a final decision to block the deal.

The operation, announced a year and a half ago, was approved in several countries, including by the European Commission last month, and would make Microsoft the world's third largest company in the video games sector.

However, the acquisition was blocked in the United States and the United Kingdom due to concerns from various regulators about competition in the video games industry.

Microsoft said in a statement released on Tuesday that "speeding up the legal process in the US will bring more choice and competition to the games market".

"A temporary restraining order makes sense until we can receive a ruling from the court, which is moving quickly," the company said.

In December, the FTC announced that it would try to stop the purchase of Activision Blizzard, claiming that it could harm consumers because it would allow Microsoft to take over important video game titles such as "Warcraft", "Call of Duty" or "Candy Crush".

The FTC complaint referred to previous game acquisitions by Microsoft, especially Bethesda Softworks, as an example where Microsoft made some popular game titles exclusive to the Xbox game system, despite having assured European regulators that it had no intention of doing so.