A post has briefly appeared on the US Xbox website confirming production of Halo 4.
It has since been removed by Microsoft, but an image of Master Chief and the below text almost certainly confirmed an E3 reveal for the title.
“Return to the Halo Universe,” the site's text read. “The news millions of Halo fans have waited for: Halo 4 is on the way. But that’s not all…”
The page also listed a number of other games in production, including Halo: Combat Evolved HD, Kinect Sports: Season 2, Kinect Fun Labs and Ryse. The latter is a warrior-based Kinect action title.
The most recent game in the Halo series, Halo: Reach, was released on Xbox 360 last September. It sold 300,000 units on day one in the UK alone.
Reach was the last Halo game to be developed by Bungie, before the studio signed a ten-year deal with Activision.