Microsoft will start offering two free games a month to its Xbox Live Gold subscribers. The promotion is in the vein of Sony's PlayStation Plus service, which charges a monthly fee for a rotating lineup of free and discounted games. Sony does not charge PlayStation 3 owners for access to online multiplayer gaming, which is restricted to paid Live members on Xbox 360.

Two of the first games to be available for free will be Assassin's Creed 2 and Halo 3. Microsoft made the announcement at its E3 keynote presentation, where it also revealed an Xbox 360 version of World of Tanks, the popular free-to-play PC title. The game will require an Xbox Live Gold subscription.

Check out our Xbox E3 2013 Live Blog for the latest updates!