The Kremlin on Friday said that at least three Russians freed in a landmark prisoner exchange were undercover Russian agents, a rare public admission into the work of Moscow’s top-secret security services.

Moscow said Vadim Krasikov — who was serving life in prison in Germany for the 2019 brazen murder of a former Chechen separatist commander in broad daylight in a Berlin park — was an elite operative with Russia’s FSB security agency.

Krasikov was one of the central figures in Thursday’s historic multi-country exchange, with Putin having publicly lobbied for his release in a bid to get the deal over the line in the face of hesitation from Berlin.

Russian President Vladimir Putin has portrayed them as returning heroes, personally thanking them for their service to the ‘Motherland’ and promising to shower them with state awards.

‘Krasikov is an FSB employee,’ Kremlin spokesman Dmitry Peskov told reporters on Friday.

An investigation by Bellingcat had previously revealed his links to the agency, though Friday’s admission was the first time Moscow has publicly confirmed he was a state operative.

Peskov said Krasikov served in the agency’s elite and secretive ‘Alpha’ unit alongside people who went on to be Putin’s personal bodyguards.

Amnesty International condemned Thursday what it called the ‘bitter taste’ of one of the biggest East-West prisoner swaps since the Cold War, warning it risked encouraging impunity for convicted criminals.

In a statement Mihr warned that Russian President Vladimir Putin ‘is clearly making the law instrumental in order to use political prisoners as pawns’.

‘The exchange therefore leaves a bitter taste,’ Mihr said, pointing out that on one side of the deal were ‘a murderer and other criminals who have been convicted in a fair trial’ and on the other, ‘people who have just exercised their right to free speech’.

‘The prisoner exchange is therefore a step towards broadening impunity,’ Mihr said, warning that ‘the Russian government could feel emboldened to carry out further political arrests and human rights violations with no fear of the consequences’.

German Chancellor Olaf Scholz admitted Thursday that releasing Krasikov — who German judges said had carried out the assassination on orders from Moscow — was ‘not easy.’

In return, Berlin secured the release of five German nationals — including some with dual Russian citizenship.

Russia also released three US citizens — journalists Evan Gershkovich and Alsu Kurmasheva, as well as ex-marine Paul Whelan — and some of the country’s most prominent domestic dissidents in a deal heralded by US President Joe Biden as an historic ‘feat of diplomacy.’

Peskov also confirmed that a Russian couple released from Slovenia were also spies.

Artem Dultsev and Anna Dultseva, whose two children were sent to Russia in the deal, had been posing as an Argentine couple that ran an IT businesses and art gallery in Ljubljana.

In the United States, the three freed US citizens touched down in Texas on Friday for medical checks after earlier landing at Joint Base Andrews, just outside Washington.

Their arrival on US soil late Thursday was met by cheers from family and friends as they disembarked a plane, before each embracing Biden and Vice President Kamala Harris.

In total, 24 prisoners were freed — eight by the West, 15 by Russia and one by Russia’s ally Belarus.