WATCH: The 10 people suspected of spying for Russia boarded a plane at LaGuardia Airport in New York on July 8, bound for Vienna as part of the presumed spy swap.
The U.S. government has confirmed that a spy swap took place between 10 suspected Russian spies in U.S. custody and four people imprisoned by Russia for alleged ties to Western intelligence services.
In a statement, U.S. Justice Department spokesman Dean Boyd said "the exchange of these individuals has been completed."
U.S. officials confirmed that the swap took place in Vienna, Austria earlier in the day.
Two airplanes, one from the United States, the other from Russia, sat side-by-side on the tarmac for an hour and a half and then flew off.
The rendezvous was to conduct the biggest spy swap between the two countries since the Cold War. The prisoners -- 14 in total -- were presumably on their way to freedom in Russia or the West.
Aboard the American plane, which arrived from New York, were 10 Russian agents arrested in America on June 27. They include nine Russian citizens and a Peruvian born U.S. citizen.
It's still not clear who was aboard the plane arriving from Moscow. But the prisoner exchange was to include four other Russians held for alleged contact with Western intelligence agencies. The best-known among them is arms-control expert Igor Sutyagin.
After leaving Vienna, the Russian plane headed for Moscow while the American plane flew to a British air force base in southern England. It was not immediately clear what the American plane's next destination would be -- if any.
All 10 of the agents had lived in the United States for a decade or more, most of them under assumed names. They pleaded guilty in a New York federal court on July 8 to charges of acting as unregistered agents of a foreign government, a lesser charge than spying.
An 11th suspected member of the ring earlier fled authorities in Cyprus after being released on bail.
Russian Spy Ring
The ring is reported to have been tasked with developing contacts to gain information about the U.S. power structure. None is believed to have infiltrated the U.S. government or obtained classified information.
New information has emerged that seemed to indicate the spy swap has been in the works for well over a month.
Speaking on condition of anonymity, a White House official told the AP that the Obama administration began deliberations on June 11 about a spy swap with Moscow, well ahead of the arrests.
In the course of ensuing negotiations with Moscow, the United States put forward the names of the four people who were released by Russia as its part of the bargain, the official said.
The Russian agents had been under observation by U.S. authorities for a decade. The decision to move against the Russians was triggered by indications that some planned to leave the United States this summer, the official said.
Robert Baum, a lawyer for Russian agent Anna Chapman, told reporters after the pleas that under the deal his client will be barred from ever returning to the United States without special authorization from Washington.
"Under the agreement that she signed, she can only come back to the United States after direct authorization by the United States government," Baum said. "It is highly unlikely they would ever grant such authorization. I can tell you that she would have preferred to stay in the United States and work."
Chapman, whose pictures have been widely shown in tabloids around the world, ran a successful real estate business which she must now abandon.
The only non-Russian in the suspected ring, Vicky Pelaez, had worked for a Spanish-language newspaper in New York. Her lawyer, John Rodriguez, told reporters Moscow offered her a pension and home in Russia as part of the exchange deal.
"The promises made by the Russian government to my client were a $2,000 pension for life, wherever she travels," Rodriguez said. "[Also] that she can go to Russia and, upon arriving in Russia, she can leave and go to any country in the world. In this case she is going to Peru."
The four prisoners to be released by Moscow in the exchange include three convicted of spying for the West -- in addition to Sutyagin, Alexander Zaporozhsky and Sergei Skripal -- and Gennady Vasilenko, who is reported to have been jailed for illegal arms possession.
Russia's state RIA news agency quotes Russian President Dmitry Medvedev's spokeswoman, Natalya Timakova, as saying he signed a pardon for the four.
Sutyagin's lawyer, Anna Stavitskaya, has said he is suffering from severe psychological problems after incarceration in a far north prison camp since 2005.
Sutyagin, who co-authored a book on the Russian strategic nuclear forces, worked previously at the Russian Academy of Sciences' Institute for the Study of the United States and Canada. He was charged with passing classified information to a London-based firm but maintains he only provided information that was available in open-sources.
Zaporozhsky is a former colonel in Russia's Foreign Intelligence Service. Skripal is a former colonel of Russia's military intelligence, and Vasilenko is a former KGB agent.
The swap is seen as ending a potentially damaging chapter in U.S.-Russian relations, which hit a new high during a White House visit by Medvedev just days before the arrests of the ring in the United States.
U.S. State Department spokesman Mark Toner said on July 8 that "no significant national security benefit would be gained from the prolonged incarceration in the United States of these 10 unlawful agents."
Officials on both sides have told news agencies privately that Moscow and Washington feel they have too great an interest in improving their ties to let the spy case set relations back.
compiled from agency reports