The detention of a dual Russian-American citizen has come to light in southern Russia.
On January 25, court documents accessed by RFE/RL's Caucasus.Realities in Kabardino-Balkaria, a Russian republic in the North Caucuses, said an individual identified by the initials K.T.N. has been detained in the region since November.
The detained individual is accused of "participating in an illegal armed group, terrorist activities and undergoing appropriate training."
The accused has so far refused to testify. His lawyer said there is no evidence of his involvement in the crimes he is charged with.
A senior investigator of Russia's Federal Security Service (FSB) in Kabardino-Balkaria is investigating the case.
Human rights campaigners and legal experts in Russia say individuals passed on as militants by the country's security services often claim to have confessed to alleged crimes because of torture during the preliminary investigation.
Moscow and Washington exchanged dozens of prisoners in the largest swap since the Cold War in August. A few U.S. citizens are still believed to be imprisoned in Russia.