So far only two factions have been confirmed for Battlefield 3: USMC (United States Marine Corps), and Russian forces. Factions on Battlefield 3 will have faction specific weapons and unlocks, unlike Bad Company 2.

Asta am vazut pe net de ceva vreme.

Am urmarit si eu cateva clipuri ale tipului ala. Face exact ce trebuie, joaca pt echipa, face maxim de damage cu minim de gloante risipite. Deci nu ia bonus pt supresion fire

De asemenea am mai gasit asta

During Gamescom 2011, multiple bits of news about Battlefield 3 hit the net. One such piece of news is that when a kit is completed, you can unlock the other faction's weapons. There is no real information on how a kit can be completed. It may be similar to gun leveling system, getting a certain amount of kills/awards with a kit will help to complete it's overall progress. Once you complete a kit in Battlefield 3, you will have access to both faction's weapons.

If you're playing as a US soldier in Battlefield 3 and your kit is completed, you could change your weapon to an AK if you would like.