Russia's Federal Security Service announced Tuesday it had detained a CIA officer during an attempt to recruit a Russian agent, saying the American had brought lots of cash, technical devices and "appearance disguising means".

The FSB, the successor to Soviet-era KGB, identified the officer as Ryan Christopher Fogle and said he had been "working under the guise of" third secretary in the political department of the US embassy in Moscow. It said Fogle was detained Monday night.

Russia's Foreign Ministry summoned US Ambassador Michael A McFaul to appear on Wednesday to respond to the accusation.

Photographs that appeared on Russian news sites on Tuesday afternoon showed a man in a blond wig, a blue checked shirt and a baseball cap being pinned to the ground, evidently by a Russian officer, and later sitting at a desk in an FSB office, grim-faced.

Russian news sources also featured the text of a letter, allegedly addressed to a recruit, that instructs the recipient to create a Gmail account that will be used for covert contacts. The letter, signed "your friends", offers $100,000 "to discuss your experience, expertise and cooperation", with much greater rewards for answering "specific questions". It goes on to say "we can offer up to $1 million a year for long-term cooperation, with extra bonuses if we receive some helpful information". Communications were to be addressed to an enigmatic e-mail address, unbacggdA@gmail.com.

"This is a down payment from someone very impressed with your professionalism and who would greatly appreciate your cooperation in the future," the letter says.

Fogle was taken to FSB headquarters and then delivered to officials at the American Embassy, the statement said. The FSB went on to say its counter-intelligence service has documented a series of recent attempts by the US to recruit officers from Russian law enforcement and "special departments."