A suspected ringleader of the 2012 terrorist attacks in Libya's Benghazi has been apprehended by a US special operations team during a secret raid in the northern African country.

Ahmed Abu Khattala was detained near Benghazi by American troops supported by the FBI and is now in US custody "in a secure location outside Libya", the Washington Post reported.

Khattala and others were charged in connection with the Benghazi attacks in which the US ambassador in Libya, Chris Stevens, and three other embassy staff were killed during a rocket bombardment.

The senior leader of Ansar al-Sharia, designated a terrorist organisation by the State Department in January, is considered specifically responsible for the attack, which took place on 11 September 2012.

"There were no civilian casualties related to this operation, and all US personnel involved in the operation have safely departed Libya," Pentagon press secretary Rear Adm John Kirby wrote in a statement.