Ex-US Marine Trevor Reed was serving a nine-year sentence in Russia after being convicted in 2019 of endangering the lives of two police officers, while Russian pilot Konstantin Yaroshenko was in US jail on drug charges.
Russia has said it had traded Trevor Reed, a former US Marine held in a Russian jail, for Russian citizen Konstantin Yaroshenko, who was serving a 20-year sentence in the United States.
The prisoner swap took place on Wednesday as the result of a lengthy negotiation process, foreign ministry spokesperson Maria Zakharova said.
The prisoner trade comes at a time of soaring tensions between Moscow and Washington over Russian onslaught on Ukraine.
US President Joe Biden, in a statement, welcomed Reed's release from detention in Russia.
Footage from state TV channel Rossiya 24 showed Reed being escorted to Moscow's Vnukovo Airport, from where he was flying back to the United States, RIA news agency reported.
"Today, our prayers have been answered and Trevor is safely on his way back to the United States", Reed's family said in a statement.
"While we understand the interest in Trevor's story - and as soon as he's ready, he'll tell his own story, we'd respectfully ask for some privacy while we address the myriad of health issues brought on by the squalid conditions he was subjected to in his Russian gulag," they said.
Reed, from Texas, was serving a nine-year sentence in Russia after being convicted in 2019 of endangering the lives of two police officers while drunk on a visit to Moscow, which he denied.
The United States called his trial a "theatre of the absurd".
Lack of proper medical care
Reed's parents said in March he had gone on hunger strike to protest against being put in solitary confinement, and he had not been receiving proper medical care despite fears that he had tuberculosis.
Russia's Federal Penitentiary Service in March denied that Reed had been in contact with anyone suffering from TB and said that repeated tests for the illness had come back negative.
It described his health as satisfactory and said that medical workers were constantly monitoring him.
Yaroshenko, a Russian pilot serving a prison sentence for conspiracy to smuggle cocaine into the United States, is expected to arrive back in Russia shortly, his wife told TASS news agency.