The US has confirmed 24 people were involved in a prisoner exchange between Russia and some Western countries including the US and Germany.
Among the prisoners being released are the US citizens Wall Street Journal reporter Evan Gershkovich and former Marine Paul Whelan, US President Joe Biden says.
As part of the deal, Russian security service hitman Vadim Krasikov is also being exchanged from Germany.
There has been speculation for days of a major swap between Russia and Western countries, which was heightened after several prisoners in Russia were moved from their prison cells to unknown locations.
Evan Gershkovich
US journalist Evan Gershkovich was sentenced to 16 years in a high-security penal colony earlier this month, after being convicted on espionage charges.
The Wall Street Journal (WSJ) reporter was first arrested last March while on a reporting trip in the city of Yekaterinburg, about 1,600km (1,000 miles) east of Moscow, by security services.
Prosecutors accused him of working for the Central Intelligence Agency (CIA), accusations that Mr Gershkovich, the WSJ and the US government vociferously deny.
It marked the first conviction of a US journalist for espionage in Russia since the Cold War ended more than 30 years ago. After his initial arrest he was held in Moscow’s notorious Lefortovo prison.
Paul Whelan
Paul Whelan, 54, was given a 16-year jail sentence in 2020 after being arrested in Moscow on suspicion of spying in 2018.
The ex-US Marine is a citizen of four countries – the US, Canada, the UK and Ireland. His lawyer said he was being held in a prison in the Mordovia region.
After being discharged from the military in 2008 for bad conduct, he become a security consultant and started to travel back and forth to Russia for work.
In December 2018, he was arrested by Russia’s FSB state security agency, which claimed he had been “caught spying” in Moscow. His family has always denied the charges.
Alsu Kurmasheva
On the same day Mr Gershkovich was convicted, Russian-American journalist Alsu Kurmasheva was sentenced to six-and-a-half years in a medium-security prison after a secret trial.
An editor for Radio Free Europe/Radio Liberty, which is funded by the US government, she was convicted of spreading false information about the Russian military.
Her husband Pavel Butorin has said that was she arrested over the book “Saying no to war”, which the radio’s Tatar-Bashkir language service published last year and was a collection of stories about Russians opposed to the war in Ukraine.
Ms Kurmasheva holds US and Russian citizenship and lives in Prague with her husband and two daughters.
She was stopped in June 2023 at Kazan International Airport, after travelling to Russia to visit her mother. Both her passports were taken. She was then arrested in October as she waited for her passports to be returned.
Vladimir Kara-Murza
Vladimir Kara-Murza is a prominent Russian dissident and one of the most vocal remaining opponents of President Vladimir Putin’s regime.
The 42-year-old has been an outspoken critic of the war in Ukraine and the internal crackdown on dissent in Russia.
In 2023, he was sentenced to 25 years in prison for spreading “false” information about the Russian army and being affiliated with an “undesirable organisation”.
Mr Kara-Murza – a former journalist and politician – denied all the charges.
A dual British-Russian citizen, he had spent his term in a prison colony in Siberia, where his wife says he developed a neurological condition as a result of being poisoned.
Ilya Yashin
One of Russia’s most prominent opposition figures, Ilya Yashin was jailed in 2022 for “spreading fake news” about the country’s military.
He was arrested after he condemned suspected Russian war crimes in Bucha, the Ukrainian town where Russian troops are alleged to have executed dozens of civilians.
Following the death of Alexei Navalny (former opposition leader) in prison, Mr Yashin said he feared for his life, and insisted he would not agree to being part of a prisoner swap with the West.
He previously accused President Vladimir Putin of going “mad with power” in a series of letters from the prison in the western Smolensk region where he was being held.
Oleg Orlov
Oleg Orlov is a Russian human rights activist who was jailed in February for calling Russia a fascist state and criticising the war in Ukraine.
Previously the chair of the Nobel Prize-winning organisation Memorial, he was handed a two-and-a-half-year term for “repeatedly discrediting” the Russian armed forces.
In an appeal aginst his sentence in July, the 71-year-old compared the Russian justice system to that of Nazi Germany.
His sentencing followed a retrial. In the original trial in October last year, he received a 150,000 rouble fine (£1,290; $1,630) and walked free from the court. His later conviction marked a hardening of repressions against opponents of the war.
Lilia Chanysheva
Lilia Chanysheva was sentenced to nine-and-a-half years in prison earlier this year after being accused of extremism by authorities.
She had served as a local coordinator with the late opposition leader Alexei Navalny’s anti-corruption network.
Initially sentenced to seven years in 2023, prosecutors appealed against the sentence and told officials it was too lenient. She was most recently held at a centre in the Perm region.
Ms Chanysheva was the first of Mr Navalny’s allies sentenced on the charge. Most of his other activists have fled Russia into exile.
Ksenia Fadeyeva
Ksenia Fadeyeva was sentenced to nine years in prison by authorities after she was accused of organising an extremist group.
She had been a local organiser with Alexei Navalny’s anti-corruption foundation in the Siberian city of Tomsk – where she was subsequently detained.
Her lawyers argued that she had ended her association with the organisation before it was designated an extremist group in 2021.
Most of Mr Navalny’s former staff and allies have been forced to flee Russia into exile in recent years, as the Kremlin has ramped up repression of opposition groups.
Who are the Russians released by the West?
One of the most high-profile prisoners to be released back to Russia is Federal Security Service (FSB) agent Vadim Krasikov, who was serving a life sentence in Germany for the 2019 murder of an exiled Chechen commander in a Berlin park.
During his trial, prosecutors said he was acting on orders from Russia, and that he belonged to a highly secretive Vympel unit of the FSB.
Lawyers defending him insisted he was a construction worker, not a hitman. He denied being known as Krasikov, and identified himself as Vadim Sokolov, the name on the passport he was travelling with.
In a recent interview with US talk show host Tucker Carlson, Russian President Vladimir Putin confirmed his country was seeking “patriot” Krasikov’s release in exchange for US journalist Evan Gershkovich, who is also part of this deal.
Roman Seleznev
The son of Russian MP, Roman Seleznev was found guilty of running a hacking scheme in 2017, that caused $169m (£131m) in damages.
US officials said he stole credit card data from US restaurants, and sold it on the black market.
He was sentenced to 27 years in prison for the scheme he ran between 2009 and 2013.
According to the Justice Department, Mr Seleznev hacked into retail point-of-sale systems and installed malicious software that enabled him to steal millions of credit card numbers from more than 500 American businesses and 3,700 financial institutions.
His politician father, Valery Seleznev, an ally of President Vladimir Putin, said the sentence against him was “passed by man-eaters”.
This story will be updated as the names of more released prisoners are confirmed