Russia reveals Moscow CIA station chief's identity
Russia has named the alleged US intelligence chief in Moscow - a move seen as breaching diplomatic protocol.
It follows Moscow's decision to expel US diplomat Ryan Fogle, who was accused of trying to recruit a Russian intelligence officer as a spy.
Mr Fogle, a purported CIA agent, was arrested on Tuesday while wearing a blond wig and was briefly detained.
Russia says it warned the CIA Moscow station chief in 2011 to stop the "provocative" recruitment of spies.
An unnamed official of the Russian FSB security services told the Interfax news agency on Friday that if recruitment attempts continued, the FSB "would take 'mirror' actions in relation to CIA officers".
The report gave the full name of the alleged CIA (Central Intelligence Agency) chief of station in Moscow. However, it is not clear if the same person remains in the post.
Mr Fogle is said to have been a third secretary at the US embassy in Moscow. He has been declared "persona non grata" for what the Russian foreign ministry called "provocative actions in the spirit of the Cold War".
He has been ordered to leave Russia but it is not clear whether he has already done so.
Russia said Mr Fogle was caught while trying to recruit an FSB counter-terrorism agent in the Caucasus.
The Kommersant newspaper said he was investigating the suspects in the Boston Marathon bombing attacks, who came from the Caucasus.
The FSB said another alleged spy, also a third secretary, was caught and expelled in January.
US officials have refused to comment on the naming of the alleged CIA chief.
"We still feel that we have a very positive relationship, and one that we can continue to work together on areas where we agree," said US state department spokeswoman Jen Psaki, quoted by the AFP news agency.
"There are still areas, of course, where we disagree. But I'm not going to weigh in further on the impact here."
A spokesman for Russian President Vladimir Putin told the Itar-Tass news agency: "This does nothing to contribute to the further building of mutual confidence between Russia and the US."
Relations between the two countries have been strained, most recently over the conflict in Syria. Russia backs the government, while the US supports the rebels.