Russia and the United States conducted the biggest spy swap since the Cold War on Friday, trading agents at the airport in Vienna, Austria, in the climax to a drama that had threatened the recent progress made in US-Russian relations.

Sutyagin 'in UK'

Among the four convicted spies pardoned by Russia, was Igor Sutyagin, an arms-control expert who was sentenced to 14 years in prison in 2004 for spying for the US.

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Sutyagin, convicted of handing over classified information to a British company that Russia claimed was a CIA cover denied he was a spy for 11 years, saying the information came from open sources.

After several days of silence, Sutyagin is beleived to be in Britain. Dmitry Sutyagin, his brother, told the AFP news agency that he called his wife on Saturday, saying he was at a hotel in a small town near London.

According to British media reports, Sutyagin and Sergei Skripal, a former colonel with Russian military intelligence [GRU] convicted of spying for Britain, were dropped off in the UK, before the plane continued on to the United States.

The British Home Office would not confirm Sutyagin was in the UK.

News blackout

Russia virtually imposed a news blackout on Saturday on questions linked to the 10 returned agents, with no information on their whereabouts coming from the media or Russian authorities.

"We still do not comment on these events," a spokesman for Russia's foreign intelligence service, SVR, told AFP.

Although several television channels mentioned the spy story, they focused on the four Russians convicted of spying for the West.

However, the country's top sensationalist website,, said that at least one of the 10 agents, Anna Chapman, had contacted her family upon arrival.

"[She] called her sister from the Domodedovo airport and said a few words: 'Everything is fine, we've landed,'" the report quoted an unidentified family friend as saying.