Hideo Kojima has announced Metal Gear Solid: Ground Zeroes, the next title in the series creator's esteemed MGS franchise.

Metal Gear Solid: Ground Zeroes has been built using Kojima Productions' next-generation Fox Engine and, for the first time, takes the stealth series open world.

The title was announced during an event marking the 25th anniversary of Metal Gear earlier this morning.

Details of the game were reported via Twitter users attending the event, with one attendee calling the game's demo "AMAZING".

"Demo of "Metal Gear Solid Ground Zeroes", started w cutscene (all realtime), went into gameplay, open world, night, raining, base. AMAZING", said one Twitter user.

"Snake crawled @ avoiding searchlights, killed guard, rode jeep, called in heli for evac. Sounds like MG, but the scale & atmosphere... Wow."

The demo was reported to be running on a PC "at current-gen specs" by another person in attendance.

It isn't yet known whether Ground Zeroes is targeted at current or next-gen consoles, which platforms the game will launch on, or when it's due for release.

As well as announcing Metal Gear Solid: Ground Zeroes, Konami also revealed this morning that a Metal Gear movie was in the works.