Dec. 31 (UPI) -- Russian officials have arrested a U.S. citizen supposedly caught in the act of spying in Moscow, the Federal Security Service of Russia said Monday.
The citizen, Paul Whelan, was apprehended Friday "during a spy action," the FSB said in a statement.
Russian state-run media TASS first reported the arrest Monday.
The U.S. Embassy in Moscow had no information on the arrest and referred questions to the State Department in Washington.
U.S. authorities nabbed their own Russian citizen, Maria Butina, who pleaded guilty to espionage earlier this month. She confessed to befriending influential pro-gun groups such as the National Rifle Association, an effort Butina said was backed by the Kremlin.
Russian officials denied Butina is one of their agents.
There's no connection between Butina and the arrest of Whelan, but Russia has a history of arresting foreigners to use for prisoner swaps to get its people back.
Russian President Vladimir Putin said the "law of retaliation states, 'An eye for an eye or a tooth for a tooth,' but "we will not arrest innocent people simply to exchange them for someone else later on."
Putin said Butina was not under the direction of the Russian government or its agencies and she only confessed to avoid a longer prison term.