The Biden administration has offered to trade Russian arms dealer Viktor Bout for basketball star Brittney Griner and convicted spy Paul Whelan.

Griner has been detained in Russia since February on drugs charges, while Whelan, a former US Marine, was convicted in 2020 of espionage and is currently serving a 16-year sentence in a Russian prison.

The Biden administration has been working for several months to secure the two Americans’ release, and that Biden himself has backed the prisoner swap offer.

Bout was arrested in Thailand in 2008 and extradited to the US two years later. He was found guilty of arming a terrorist group and conspiring to kill US nationals, and was sentenced to 25 years in a federal prison in 2012. Prior to his arrest and conviction, Bout was one of the world’s most prolific arms dealers, whose life inspired the 2005 Hollywood movie ‘Lord of War.’

Secretary of State Tony Blinken told reporters on Wednesday that he would speak to Russian Foreign Minister Sergey Lavrov about a potential prisoner swap over the coming days. While Blinken said that the US had made a “substantial offer” to Moscow, he did not mention Bout.

Meanwhile in Moscow, Griner’s trial continued on Wedensday, with the athlete claiming that she had been provided with an inadequate translation of the circumstances of her arrest. Griner earlier claimed that she did not know how cannabis oil she was caught with entered her belongings, and said through her lawyer on Wednesday that she “respects Russian laws and never intended to break them.”

Griner faces a term of up to 20 years in prison if convicted. Her detention has been authorized up until December 20, and her trial resumes on August 2.