"Russia's counterintelligence agency has detained a CIA agent in Moscow trying to recruit an officer of the Russian secret service, the Federal Security Service (FSB) announced. The agent was operating under guise of career diplomat."
According to Reuters, the Russian foreign ministry has summoned U.S. Ambassador Michael McFaul for a discussion.
The BBC adds that:
"The alleged agent was held overnight before being released to U.S. officials, Russia's Federal Security Service said. He is said to have been working as a secretary at the U.S. embassy in Moscow. The man was reportedly arrested with a large sum of money, technical devices and written instructions for the agent he had tried to recruit."
Other news outlets have identified the alleged agent, but NPR has not independently confirmed his name or that he is in fact a CIA officer.