The Pentagon says four detainees held at the Guantanamo Bay U.S. military detention facility have been repatriated to Afghanistan.
A Pentagon statement said on December 20 said the men -- Shawali Khan, Khi Ali Gul, Abdul Ghani, and Muhammad Zahir -- had been moved from the prison after a comprehensive review of their case.
An unnamed U.S. official said the four detainees were flown to Kabul overnight aboard a U.S. military plane and released to Afghan authorities.
The U.S. Embassy in Kabul on December 20 issued a statement saying it had "full confidence in the Afghan government's ability to mitigate any threats these individuals may pose and to ensure that they are given humane treatment."
The statement said the transfer "demonstrates Afghan sovereignty and U.S. trust in the strength of Afghan government institutions."
U.S. officials are citing the transfer as a sign of their confidence in new Afghan President Ashraf Ghani.
Obama administration officials said they worked quickly to fulfil the request from Ghani, in office just three months, to return the four -- long cleared for release -- as a gesture of reconciliation and a mark of improved U.S.-Afghan relations.
There is no requirement that the Afghan government further detain the men. Afghanistan's High Peace Council, a government-appointed group, has confirmed the transfer, without identifying the men.
The council said the four "will be reunited soon with their families."
It also requested the repatriation of the eight Afghans who are among the 132 detainees remaining at Guantanamo.
The number is the lowest since shortly after it opened nearly 13 years ago in the wake of the September 11, 2001, terrorist attacks. Out of the remianing 132, some 64 have already been approved for transfer.
U.S. Presdient Barack Obama pledged to shut the prison, which is located on Cuban territory, when he took office nearly six years ago, citing the damage it inflicted on the United States' image around the world.
But Obama has been unable to do so, partly because of obstacles posed by the U.S. Congress.