The first in-game Halo 4 screenshots have leaked online ahead of a Microsoft-planned announcement later today.

Two screenshots, courtesy of the naughty Gamerlive.tv (via NeoGAF) show Master Chief resplendent with, what's that, oh yes, Halo's Battle Rifle.

Paul Featherstone, assistant director of photography at 343 Industries, who took the screenshots, claimed they were "100% untouched", using a "debug cam with in-engine Depth-of-field".

Halo 4 principal engine programmer Corrinne Yu took to her Twitter page to hype up the upcoming Xbox 360 exclusive.

"It's the best looking game on Xbox and any other consoles we ever made and we're all from AAA studios," she said. "So proud of team."

Halo 4 is developed by 343 Industries, Microsoft's in-house Halo franchise studio. It is the developer's first title, and the first FPS in the Halo series not to be developed by creator Bungie.

More information on Halo 4 is expected this afternoon.