Meanwhile, Russia's Itar-Tass news agency reported to the contrary, saying Sutyagin would be extradited to the UK in exchange for one person detained there. The agency supported the claim with a statement from Stavitskaya herself.

“Yes, Sutyagin will be indeed transferred to Great Britain in exchange for one person that will be handed over to Russia,” Anna Stavitskaya reportedly said.

Neither the Federal Security Service nor the Justice Ministry issued any official comment on the issue by Wednesday evening. Russia's Foreign Intelligence Service also refused to confirm or deny the report.

Late on Wednesday the Russian service of Reuters news agency quoted an unnamed source in the US government as saying that President Barack Obama’s administration is considering the possibility of a swap deal.

“This is common practice. It has been done many times before,” the agency quoted its source as saying. According to Reuters, the official said that the Russian spy suspects must plead guilty so that a swap deal could be launched.

Igor Sutyagin was head of a department in the Institute of USA and Canada at Russia’s Academy of Sciences, which dealt with military policies. He was detained in 1999 and found guilty of transferring classified information to representatives of UK consulting firm “Alternative Futures”. According to the FSB, the firm was linked to US intelligence and had nothing to do with science. The information included details of new arms systems and nuclear submarines. Sutyagin insisted that he had collected the information from public sources.

In 2004 the scientist was sentenced to 15 years in prison and has been serving it in Arkhangelsk.

Another figure in the spy swap is reportedly former Russian intelligence officer Sergey Skripal, who was sentenced to 13 years in prison for spying for UK in 2006. However, his lawyer Elena Lebedeva-Romanova has not commented on the news, Rosbalt news website reported.

Chris Lapetina, a strategist for the US Democratic Party, says Russia and the US are making very good progress getting along, and have very serious issues to take care of, so he believes the Obama administration doesn’t want to get bogged down in creating a problem with Russia.

“I think Obama and hopefully the Russian leadership recognize that it doesn’t do any good either historically or even politically for either of the leaders to get bogged down in things that really don’t matter,” he said. “I think we really crossed the Rubicon. Even though we may spy on each other’s countries, it doesn’t have to be a field of tension and bring us to a point where we can actually have some kind of conflict between the countries.”

Swapping agents and intelligence officers is a long-standing Cold War tradition, says Russia's former deputy Foreign Minister Georgy kunadze. In the 1970s the USSR added to it – it came up with swapping agents for dissidents.

"Apparently, nowadays this tradition is going to be revived. I would say it’s an interesting zigzag of history,” Kunadze said.

Editor-in-chief of “Slovo” newspaper Viktor Linnik said that, regardless of whether a deal has indeed been arranged, spy swaps are generally a common phenomenon.

“We have heard a lot about them in the past,” Linnik said. “I am not surprised we are having this one. I think that perhaps the whole story with the Russian spy ring was invented to release Mr. Sutyagin…just to have a good excuse to end this story peacefully.”

Russia’s ex-director of Federal Security Services (the FSB), Nikolay Kovalev believes it is most unlikely that Sutyagin will be exchanged for the alleged Russian spies currently detained in the US.

“The man, whose name was forgotten, just reminded people of himself,” Kovalev told RIA Novosti news agency.