Russian security services have held a US diplomat they claim is a CIA agent after catching him trying to recruit a Russian agent.
The FSB agency said that Ryan Fogle, a third secretary at the US Embassy in Moscow, was carrying special technical equipment, disguises, written instructions and a large sum of money when he was detained overnight.
State television showed pictures of a man said to be Mr Fogle sitting at a desk in FSB offices. The FSB said Mr Fogle was handed over to US officials.
US ambassador Michael McFaul refused to comment.
The announcement came at an awkward time, just days after a visit by US Secretary of State John Kerry during which Washington and Moscow agreed to try to bring the warring sides in Syria together for an international peace conference.
The Russian Foreign Ministry said it had summoned U.S. Ambassador Michael McFaul over the case and a Russian television station published photographs which it said showed Fogle being detained, apparently wearing a blond wig. Diplomats accused of espionage are usually expelled or withdrawn.
“On the night of May 13-14, a staff employee of the CIA, Ryan Christopher Fogle ... was detained by counter-espionage organs of the Russian FSB while attempting to recruit an employee of one of the Russian special services,” the FSB said.
“Recently American intelligence has made multiple attempts to recruit employees of Russian law enforcement organs and special agencies, which have been detected and monitored by Russian FSB counterintelligence,” it said in a statement.
The US ambassador, Mr McFaul, a former adviser to President Barack Obama, was holding a live question-and-answer session on Twitter as news of the detention was announced, but refused to take questions on the matter.
Russia Today television published photographs on its website which it said showed Fogle being detained. In one photograph, a man lies face-down on the ground with his arms held behind his back by another man, and apparently wearing a blond wig. Another image showed two wigs, apparently found on him, as well as three pairs of glasses, a torch, a mobile phone and a compass. Aldo displayed was a wad of €500-euro notes and an envelope addressed to a "dear friend".
Despite the end of the Cold War, Russia and the United States still maintain active espionage operations against each other.
Last year, several Russians were convicted in separate cases of spying for the US and sentenced to lengthy prison sentences. The detention of Mr Fogle, however, appeared to be the first American diplomat accused of spying in about a decade and seemed certain to aggravate already strained relations between the two countries.
AP/Reuters