The Marine Corps Security Force Regiment is a dedicated security

Security

Security is the degree of protection against danger, damage, loss, and crime. Security as a form of protection are structures and processes that provide or improve security as a condition. The Institute for Security and Open Methodologies in the OSSTMM 3 defines security as "a form of protection...

 and anti-/counter-terrorism

Counter-terrorism

Counter-terrorism is the practices, tactics, techniques, and strategies that governments, militaries, police departments and corporations adopt to prevent or in response to terrorist threats and/or acts, both real and imputed.The tactic of terrorism is available to insurgents and governments...

 unit of the United States Marine Corps

United States Marine Corps

The United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...

. It provides security forces to guard high-value naval installations, most notably those containing nuclear vessel

Nuclear marine propulsion

Nuclear marine propulsion is propulsion of a ship by a nuclear reactor. Naval nuclear propulsion is propulsion that specifically refers to naval warships...

s and weapons

Nuclear weapon

A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

. It also provides Fleet Antiterrorism Security Teams (FAST) and Recapture Tactics Teams (RTT). Marines who complete Security Force training are assigned a secondary Military Occupational Specialty of 8152 (Marine Corps Security Force Guard), while instructors can earn 8153 (Marine Corps Security Force Cadre Trainer).
The unit was initially organized as the Marine Detachment, Naval Operation Base

Naval Station Norfolk

Naval Station Norfolk, in Norfolk, Virginia, is a base of the United States Navy, supporting naval forces in the United States Fleet Forces Command, those operating in the Atlantic Ocean, Mediterranean Sea, and Indian Ocean...

 in 1920.