The NCS' primary action arm is the Special Activities Center, which conducts direct action-like raids, ambushes, sabotage, assassinations, unconventional warfare (e.g. training and leading guerrillas), and deniable psychological operations, the latter also known as "covert influence". While special reconnaissance may be either a military or intelligence operation, these usually are executed by SAD officers in denied areas. Paramilitary Operations Officers are chosen mainly from the ranks of U.S. special operations forces. SAD operatives are the most specialized because they combine the best special operations and clandestine intelligence capabilities in one individual. They operate in any environment (sea, air, or ground), with limited to no support. They originate in the SAD's Special Operations Group (SOG), considered one of the most elite special operations units in the world.