In return for the release of two imprisoned American citizens, Russia has apparently demanded the release of the Russian Vadim Krassikov, who was sentenced to life imprisonment in Germany for the Tiergarten murder.

The spokesman for the US National Security Council, John Kirby, confirmed on Friday the US news channel CNN that Russian officials had made such a move.

However, he firmly rejected the request.

"Holding two US citizens hostage in exchange for a killer in a third country is not a serious counteroffer," Kirby said.

"It is a malicious attempt to evade a very serious US offer and proposal." Russia must take the American offer seriously.

Conversation between Blinken and Lavrov

The United States is currently trying to free basketball player Brittney Griner and former US soldier Paul Whelan, who are also incarcerated in Russia.

Washington has therefore submitted an offer to Moscow, which was also the subject of talks between American Secretary of State Antony Blinken and Russian Foreign Minister Sergey Lavrov on Friday.

According to media reports, the US plan communicated weeks ago involves an exchange of the two American citizens with the Russian arms smuggler Viktor Bout, who is in prison in the US.

CNN then reported on Friday, citing informed circles, that Russian representatives had already requested through informal channels at the beginning of the month that the United States release Vadim Krassikov as part of a prisoner swap.

The so-called Tiergarten murder had led to diplomatic upheavals between Germany and Russia.

Both states expelled several diplomats from the other country.

In August 2019, a Chechen-born Georgian was shot dead in the Kleiner Tiergarten park in Berlin.

The Berlin Court of Appeal sentenced the Russian Krassikov to life imprisonment.

The judges were convinced that he acted on behalf of Russian state authorities.

Russia denies such allegations.

Who is Krassikov?

The accused's brother-in-law testified at the hearing before the Berlin Court of Appeal that Krassikow was a colonel and had long worked for the FSB's special paramilitary unit "Wympel".

Photos from the family inventory also indicated that he belonged to this unit from an early age.

There is a picture of him wearing a t-shirt with the crest of the Special Forces Center showing a shield and sword.

Other details also suggest his work for the secret service.

So he constantly changed the number of his mobile phone, was on secrecy.

His in-laws didn't even know their daughter's cell phone number.

After a mission in Kyiv, when there were major protests on the Maidan, Krassikov is said to have broken a mobile phone after a call and thrown away the SIM card.

According to research by Bellingcat, Krassikow may have been trained in two FSB training camps in the months before his deployment in Berlin.

Radio cell data show that his mobile phone was logged into the training center area at the time.

Discussions with Germany about the claim

According to CNN, Russia's demand for the man's release was seen as problematic, especially as Krassikov is serving his sentence in Germany.

However, American representatives had contacted Germany to find out in principle whether Krassikov could become part of the swap deal, the news channel reported, citing a German government official.

But that was never seriously considered.

Basketball star Griner was arrested at Moscow's Sheremetyevo Airport in mid-February for possession of cannabis oil.

She faces up to ten years in prison for drug smuggling.

Whelan was sentenced to 16 years in prison on espionage charges in 2020.