Russia's Federal Security Service (FSB) says it has detained a U.S. citizen in Moscow over suspected spying.
The American was detained on December 28 and a criminal probe had been opened, the FSB was quoted as saying by the state-run TASS news agency on December 31.
The TASS report said the American could face between 10 to 20 years in prison if found guilty but disclosed no further details.
The announcement comes a day after Russian President Vladimir Putin said Moscow remained open to dialogue with Washington in a New Year's greeting to U.S. President Donald Trump.
Relations between the United States and Russia remain strained over a raft of issues including Russia's role in wars in Syria and eastern Ukraine, its alleged meddling in elections in the United States and elsewhere, and the poisoning of a Russian double agent in Britain.
At the end of November, Trump abruptly canceled a planned meeting with Putin on the sidelines of a Group of 20 summit in Argentina, citing tensions after Russian forces opened fire on Ukrainian Navy boats before seizing them and capturing 24 Ukrainian sailors.