Russia has charged a retired U.S. Marine arrested in Moscow with espionage, said his lawyer, who appealed the ruling.
Russia's Federal Security Service (FSB) said on December 31 that it had arrested Paul Whelan, who it said was caught carrying out an act of espionage.
The FSB has not disclosed the nature of his alleged espionage activities.
Defense lawyer Vladimir Zherebenkov said on January 3 that he had asked for Whelan to be released on bail pending the start of the trial.
Zherebenkov said the 48-year-old was "behaving in a constructive manner" and that investigators were treating him in a "humane and professional way."
Whelan, who has denied the charges, could face up to 20 years in prison if found guilty.
U.S. Secretary of State Mike Pompeo said on January 2 that the United States was seeking an explanation for why Russia arrested Whelan on spying charges and will demand his immediate return if it determines his detention is inappropriate.
The U.S. State Department said U.S. Ambassador to Russia Jon Huntsman visited Whelan at a detention facility in Moscow on January 2 and spoke by phone with his family.
Whelan's family has denied he was a spy and said he was in Moscow to attend a wedding.