Washington: The US Navy Commandos, which played a significant role in killing Osama bin Laden is known as "Team Six," an elite unit drawn from the already elite ranks of the SEALs.

The unit is so secret that the military does not openly acknowledge its existence, but its reputation has taken on near mythic proportions and features in numerous books, films and video games.

The White House and the Central Intelligence Agency have declined to openly confirm that "Team Six" led Monday's assault on Bin Laden's residence in Pakistan, though Vice President Joe Biden and the spy agency's chief Leon Panetta hailed the Navy SEALs for carrying out the operation.

Since it was created in 1980 in the aftermath of the failed attempt to rescue American hostages in Iran, Team Six has been credited with the rescue of the Governor of Grenada
in the 1983 US invasion, helping hunt down war criminals in the Balkans and liberating the American captain of the Maersk Alabama after shooting three Somali pirates in 2009.

The squad also led the operation to rescue Linda Norgrove, a British aid worker abducted by insurgents in Afghanistan, but she died in the attempt, according to US media.

The unit's number six was chosen to confuse the Soviet Union, as at the time there were only two other such teams, according to Richard Marcinko, who recounted his experience as
the first leader of Team Six in his book "Rogue Warrior."

The team faced controversy in the 1980s amid allegations of misuse of funds and equipment, with Marcinko convicted of bribery and other charges.

In the 1980s, the squad had about 90 members, but it expanded to about 200 to 300 ,according to various media reports and defence websites.

The team's members are recruited from the 2,300 men in the Navy SEALs, an acronym for Sea, Air and Land -- famous for its brutal selection and training that push the limits of
human endurance.

It takes about five years of training to earn the right to wear the trident badge of the SEALs, including underwater demolition, parachuting at high altitude and submarine operations.