Ten Russian agents who infiltrated suburban America and acted as spies have been deported to Moscow after admitting in a New York Court to having spied for Russia.
They are being exchanged for four people convicted of betraying Moscow to the West in the biggest spy swap since the Cold War.
The swap carries significant consequences for efforts between Washington and Moscow to repair ties chilled by a deepening atmosphere of suspicion.
The defendants were captured last week in homes across the north east. They were accused of embedding themselves in ordinary American life while leading double lives, complete with false passports, secret code words, fake names, invisible ink and encrypted radio.
One spy worked for an accounting firm, another was an estate agent and another a columnist for a Spanish-language newspaper.
US attorney general Eric Holder said last night the "extraordinary" case took years of work "and the agreement we reached today provides a successful resolution for the United States and its interests".
White House chief of staff Rahm Emanuel said President Barack Obama was aware of the investigation, the decision to go forward with the arrests and the spy swap with Russia.
But whether the agents provided Russia with valuable secret information is questionable.
"None of the people involved from my understanding provided any information that couldn't be obtained on the internet," defendant Anna Chapman's lawyer, Robert Baum, said.
In Russia, the Kremlin said President Dmitry Medvedev signed a decree pardoning four convicted foreign spies so that they could be exchanged for the 10 US defendants.
They are Russian citizens Alexander Zaporozhsky, Gennady Vasilenko, Sergei Skripal and Igor Sutyaginso.
Sutyagin, an arms analyst, was reportedly plucked from a Moscow prison and put on a plane to Vienna. Skripal is a former colonel in the Russian military intelligence, and Zaporozhsky a former colonel in the Russian Foreign Intelligence Service.
The US Justice Department said yesterday that some of the four prisoners were in poor health and had served lengthy prison terms.
It said three were accused by Russia of contacting Western intelligence agencies while they were working for the Russian or Soviet government.
Russia's Foreign Ministry said the exchange being conducted by its foreign intelligence service and the CIA was conducted in the context of "overall improvement of the US-Russian ties and giving them new dynamics".
A senior Obama government official said the quick and pragmatic arrangement of the spy swap with Russia showed the progress made in US-Russian relations.
The official said that by shutting down the spy ring, the US had sent a warning to other governments that might be interested in undertaking similar operations.
The 10 US spies pleaded guilty to conspiracy to act as an unregistered agent of a foreign country. An 11th defendant has been a fugitive since fleeing authorities in Cyprus following his release on bail.
Lawyer John Rodriguez said his client, Vicky Pelaez, had been given only 24 hours to agree to the "all or nothing" deal for deportation.
The defendants - led into court in handcuffs, some in prison smocks and some wearing T-shirts and jeans, provided almost no information about what kind of spying they actually did for Russia.
Asked to describe their crimes, each acknowledged having worked for Russia secretly, sometimes under an assumed identity, without registering as a foreign agent.