Seven Russian citizens who were being held by the United States at Guantanamo Bay in Cuba have returned to Moscow, the Russian foreign ministry says.
Conditions at Guantanamo Bay have been widely condemned
They are now reported to be in a pre-trial detention centre.
The men have been charged with illegally crossing borders, mercenary activity and participating in a criminal group, prosecutors say.
The men, who returned on Saturday, were all detained in Afghanistan, but have not been identified.
They were handed over after lengthy talks between Washington and Moscow.
"The decision to transfer or release a detainee is based on many factors, including whether the detainee is of further intelligence value to the United States and whether he poses a threat to the United States," the Pentagon said.
The Russian prosecutor's office has said the detainees include residents of Russia's Muslim-majority republics of Tatarstan and Bashkortostan, the city of Chelyabinsk in western Siberia, and the Caucasus region.
Pentagon officials had hinted that they were in discussions with other governments, including Russia's.
According to these officials, the United States has been holding talks over dozens of detainees.
This is further confirmation that we are now in a more fluid period with the detainees, says the BBC's Pentagon correspondent Nick Childs.
The first two detainees have been charged and the Pentagon is gearing up for its first military tribunals.
It is also saying there will be further transfers and releases, but that others among the 650 or so prisoners could be held indefinitely.
However, no more transfers are imminent, officials say.
And while London and Washington announced an agreement on the handover of five Britons nearly two weeks ago, there is no word of them actually moving.