Counter Terrorist Factions
Spetsnaz ''MVD'' or ''Vityaz'': Russian counter-terrorist group, they're right now under command of the ODON since the 2008, they're known for participate in the two chehen wars, in hostage crysis around the 1990's and 2000's and also inside the south-ossetian war against Georgia. They're known for be the only units who now at days uses weapons as the AEK-971, VSS Vitonez, SVU, etc.
Navy Seals: The Navy Seals of the US, famous for participate in the most important cold war conflicts (Korean war, Vietnam war, etc). They use weaponry as the HK 416, MP5, P226, SCAR-L.
SAS: The british Special Airforce Service are one of the most iconic special units around the globe, they were formed since 1941 and they participated since then inside lot of conflicts like the WWII, Vietnam, Cambodia, etc. Their weaponry is really extensive, but mainly are weapons from the same UK, Canada, Belgium and Germany.
Terrorist Factions
North-Caucasian Militia: After the USSR falled, the Caucasian territories became an unstable place, this milita are the fighters for the creation of a ''Caucasian emirate''. Their weaponry are mostly from the soviet union and some purchased inside the black market, like the AKM, RPK, PKM, etc.
Iraqi Insurgents: The iraqui insurgents are armed civilians and hidden military from the Iraq war of 2003-2011, they can be fighters of diferent kind, they can be arab or iraqi nationalists or ba'athists who wants to recover the old regime. Their weaponry looks like the north-caucasian militia, but most of their weapons are chinese copies of russian weaporny or weapons from the old irak army, as the AKM, PKM, SVD, etc.
Hamas (MECSF): The Hamas are armed civilians from islamic countries neighbors to Israel, they're known for be readical islamics guerrilla. Their weaponry is not completly soviet, there's too old western weapons as the XM177, L1A1/FN FAL, etc.
Mercenaries (MEC): Not all the terrorism should be about nationalism, religion and stuff like that or all terrorists should be organized and clandestine formed groups, sometimes, the illegal business is target of the counter terrorism, this faction formed by western european members are a private army who protects the projects and dirty jobs of some companies in their illegal activity. The weaponry of this faction will be a mix of easter and western european weaponry, as the MP5, AKM, M16, SVD, etc.