The United States and Russia have agreed to swap 10 Russian agents who pleaded guilty before a New York federal court in exchange of four persons incarcerated by Moscow for alleged contact with Western intelligence agencies. "The United States and the Russian Federation agreed that the United States would transfer these individuals abroad and turn them over to Russian authorities. The Russian Federation, in turn, would release four individuals incarcerated in the Russian Federation," US State Department spokesman, Mr Mark Toner, said in a statement. As part of their plea agreements, the Russian spy suspects operating in the US under false identities disclosed their true Russian identities. Each of the defendants also agreed to be immediately expelled from the US. Mr Toner said a determination to seek a rapid and comprehensive solution was made on national security and humanitarian grounds. "No significant national security benefit would be gained from the prolonged incarceration in the United States of these ten unlawful agents," he said. "The United States took advantage of the opportunity presented to secure the release of four individuals serving lengthy prison terms in Russia, several of whom were in poor health," the spokesman said. The four American spy suspects were not immediately named, but reports from Moscow indicated that the government was preparing to release Igor Sutyagin, a prominent Russian scientist who has been imprisoned for 11 years on espionage charges he has steadfastly denied. "This was an extraordinary case, developed through years of work by investigators, intelligence lawyers, and prosecutors, and the agreement we reached on Friday provides a successful resolution for the United States and its interests," Attorney General Eric Holder said. In hearings before Judge Kimba Wood in a New York court, each of the 10 defendants arrested on June 27, pleaded guilty to one count of conspiracy to act as an agent of a foreign government within the US without notifying the US Attorney General. Under their plea agreements, the defendants were required to disclose their true identities in court and to forfeit certain assets attributable to the criminal offences. The defendants known as 'Richard Murphy' and 'Cynthia Murphy' admitted they are Russian citizens Vladimir Guryev and Lydia Guryev and agents of the Russian Federation. Defendants 'Michael Zottoli' and 'Patrica Mills' admitted they are Russian citizens Mikhail Kutsik and Natalia Pereverzeva and agents of the Russian Federation.