The National Security Guard (NSG), commonly known as Black Cats, is a counter-terrorism unit of India under the Ministry of Home Affairs. It was founded on 16 October 1984, following Operation Blue Star, for combating terrorist activities and protect states against internal disturbances.

It operates under the Ministry of Home Affairs and is a task-oriented force that has two complementary elements in the form of:

o Special Action Group (SAG) comprising of the Army personnel- is the main offensive or the strike wing of the NSG, and
o Special Ranger Groups (SRG) comprising of personnel drawn from the Central Armed Police Forces/State Police Forces. They generally handle VIP securities.
o National Security Guard has been given the specific role to handle all facets of terrorism in any part of the country as a Federal Contingency Force.
o The NSG is trained to conduct counter-terrorist task including counter hijacking tasks on land, sea, and air;
o Bomb disposal (search, detection, and neutralization of IEDs),
o Post Blast Investigation (PBI),
o Hostage Rescue missions.

Operations undertaken:
o Operation Black Thunder (Golden Temple, Amritsar, 1986 & 1988)
o Operation Ashwamedh (Indian Airlines Flight-IC427 hijacking, India, 1993)
o Operation Thunderbolt or Vajra Shakti (Akshardham Temple attack, Gujarat, 2002)
o Operation Black Tornado (Mumbai Blasts, 2008)