The arrest of Russian spies in the US and the ensuing spy-swap was the result of the betrayal of a Russian intelligence officer, a Moscow newspaper reported on Thursday.  

Kommersant, the paper, claimed that Col. Shcherbakov, who worked for Russia's Foreign Intelligence Service (SVR), blew the cover of his unit.  

In late June this year, 10 Russians were arrested in New York and Washington after the FBI reportedly intercepted a message from the headquarters of Russia's intelligence service in Moscow. A week later, a spy-swap, the largest between both countries since the Cold War, was agreed and carried out in Vienna.  

The newspaper stated that the officer fled to America in June, just three days prior to President Dmitry Medvedev's official visit to Washington. His daughter has been living in the United States for several years, yet SVR remained unconcerned about the issue.

It's strange that no one questioned why a person on that level has relatives abroad. Such things are strictly monitored even in less secret organizations, Kommersant quoted a senior Russian intelligence official.

The official also maintained that SVR failed to take notice when Shcherbakov refused to accept a career promotion in 2009. The process would have forced him to undertake a lie-detector test. Other media reports also suggested that Shcherbakov's son, who worked for Russia's drug watchdog Gosnarkokontrol, left Russia for the United States earlier this year.

Kommersant also quoted an official in Kremlin as saying that Shcherbakov's fate cannot be envied.

He will carry this with him all his life and will fear retribution every day, he reportedly told the newspaper.