Jan 3, 2011 13:59 GMT  ·  By

Activision Blizzard, as the publisher, and Treyarch, as the developer, have announced the delivery of the First Strike downloadable content pack for Call of Duty: Black Ops on February 1, exclusively via the Xbox Live service from Microsoft.

Microsoft has persuaded Activision, probably by monetary means, to make First Strike a time exclusive, meaning that those who play Black Ops on the PC and on the PlayStation 3 from Sony will have to wait for a month or more in order to get the same content.

Other versions of the game, like the ones for the Nintendo Wii and DS, will probably not get any new content.

First Strike has been confirmed as delivering four new multiplayer maps for the standard game modes, called Berlin Wall, Stadium, Kowloon and Discovery.

Those who favor the cooperative game mode that pits human players against zombies will also get a new map called Ascension.

Mark Lamia, who is the leader of Call of Duty development at Treyarch, has stated, “We’re committed to supporting Call of Duty: Black Ops fans with continuous updates to the game and exciting new content that will keep our community engaged.”

Call of Duty: Black Ops will probably get at least one other DLC pack from Treyarch at some point during 2011.

The developer shipped three packs for Call of Duty: World at War while troubled Infinity Ward delivered two for Modern Warfare 2.

Call of Duty: Black Ops has already been certified as the best sold video game of last year, just as Modern Warfare 2 before it, and Activision has already said that it plans to deliver a new game in the series during 2011.

It's not clear who is leading the development effort on the new Call of Duty game but analysts say that it is unlikely that it will replicate the success of the last two installments in the franchise.