SEAL Team Six

The United States Naval Special Warfare Development Group (NSWDG), commonly known as DEVGRU and informally by its former name SEAL Team Six (ST6), is one of the United States' secretive Tier One counter-terrorism and Special Mission Units (SMUs), the other one being 1st SFOD-D (Delta Force). In a recent article, Marc Ambinder wrote that DEVGRU's designation had been changed by the Defense Department to a new name. However, the new name is currently classified. 

 This has also been the case for Delta Force, which was originally designated 1st Special Forces Operational Detachment-Delta, and is now known as Army Compartmented Elements," or "ACE.”. The vast majority of information surrounding DEVGRU is highly classified and details of its activities are not commented on by either the White House or the Department of Defense.

The origins of ST6 can be traced to the aftermath of Operation Eagle Claw, the failed 1980 attempt to rescue American hostages at the U.S. Embassy in Iran. During the Iran Hostage Crisis in 1979, Richard Marcinko was one of two Navy representatives for a Joint Chiefs of Staff task force known as the TAT (Terrorist Action Team). The purpose of the TAT was to develop a plan to free the American hostages held in Iran, which culminated in Operation Eagle Claw. In the wake of the operation's disaster at Desert 1, the U.S. Navy saw the need for a full-time dedicated Counter-Terrorist Team and tasked Marcinko with its design and development.

Marcinko was the first commanding officer of this new unit which he named SEAL Team Six (at the time, the US Navy had only two SEAL teams. Marcinko purportedly named the unit Team Six in order to confuse the Soviet intelligence as to the number of SEAL Teams in operation. It became officially operational in 1981. Marcinko himself from across the U.S. Navy’s Special Operations personnel handpicked the men in the unit. SEAL Team Six would be known as the U.S. Navy's premier counter-terrorist unit. It has also been compared to the US Army's Delta Force. Marcinko held the command of SEAL Team Six for three years from 1980–1983 instead of what was typically a two-year command in the Navy at the time. SEAL Team Six was formally created in October 1980 and an intense, progressive work-up training program made the unit mission-ready six months later. Prior to this, the existing SEAL teams had already begun counter-terrorism training, including 12 platoons in SEAL Team One on the West Coast. On the West Coast, elements of the SEAL Team One had taken the issue one-step further. They formed a dedicated two platoon group known as "MOB Six" (Mobility Six) in anticipation of a maritime scenario requiring a counter-terrorism response and had begun training to that end.

In 1987, a new unit was formed, given the official title of 'Naval Special Warfare Development Group' (NAVSPECWARDEVGRU, or DEVGRU) after SEAL Team Six was dissolved. Reasons for the disbanding are varied. But the name "SEAL Team Six" is often used in reference to DEVGRU because of their similarities as a maritime counter-terrorism unit.

Source: wikipedia.org