WASHINGTON (Reuters) -The U.S. Federal Trade Commission (FTC) asked a federal court on Thursday for a stay that would prevent Microsoft from closing its $69 billion purchase of "Call of Duty" maker Activision Blizzard.

A federal judge had ruled for Microsoft on Tuesday, saying the agency had failed to show the deal would be illegal under antitrust law. The FTC appealed that loss late on Wednesday, and Microsoft has said it would fight that appeal.

In its motion, the FTC asked for an order that would prevent the deal from closing until after the 9th U.S. Circuit Court of Appeals has ruled on a separate stay request filed with that court.

Any outstanding regulatory hurdle makes it more likely the agreement between Microsoft and Activision will expire on July 18 without the deal having been completed. After July 18, either company will be free to walk away from the deal unless they negotiate an extension.

(Reporting by Diane Bartz; Editing by Tim Ahmann and Josie Kao)