US basketball player Brittney Griner was released from a penal colony near Moscow in a prisoner swap with Russia, US and Russian officials said Thursday. Griner was freed in exchange for notorious Russian arms dealer Viktor Bout.

Negotiations on a prisoner exchange had been ongoing for months, and Griner's release had been a priority for US President Joe Biden.

"These past few months have been hell for Brittney," Biden said in remarks given at the White House Thursday. 

"She's safe, she's on a plane, she's on her way home after months of being unjustly detained in Russia, held under intolerable circumstances," he added.  

Biden and Vice President Kamala Harris spoke by phone with Griner from the Oval Office alongside Griner's wife, Cherelle, Biden tweeted soon after the release was announced. 

The Russian Foreign Ministry confirmed the prisoner swap took place Thursday at Abu Dhabi airport in the United Arab Emirates (UAE). 

A joint statement statement said the UAE and Saudi Arabia had led mediation efforts, which were a success due to the "mutual friendship" the two countries share with both the US and Russia. 

But the White House refuted the statement's claim. "The only countries that negotiated this deal were the United States and Russia," White House press secretary Karine Jean-Pierre said. "There was no mediation involved." 

The White House also said that the prisoner's exchange would "not change the US commitment to the people of Ukraine."

Long-awaited prisoner exchange

The WNBA star was arrested at Moscow's Sheremetyevo airport on February 17, for allegedly possessing vaporizer cartridges containing cannabis oil in her luggage she said was used to treat a medical condition. 

In November, she was sentenced to nine years in a Russian penal colony. 

Arms dealer Bout, who was known as the "merchant of death " at the time of a 2012 conviction for conspiracy to sell weapons to terrorists, was serving a 25-year sentence in the US. 

During his time as an international arms dealer, Bout was one of the world's most wanted men, and was known for unscrupulously selling arms in conflict regions around the world 

His life helped inspire the 2005 film "Lord of War" starring Nicholas Cage.

Former US Marine remains detained in Russia 

President Biden said Griner's release was secured after "painstaking and intense" negotiations. However, in recent weeks, US and Russian officials had expressed cautious optimism that a swap would go through.

Griner's arrest and long sentence were handed out against the backdrop of deteriorating relations between Russia and the US amid the war in Ukraine.  

The US still working to release Paul Whelan, a US citizen serving a 16-year sentence in Russia after being arrested of espionage changes in 2018. President Biden said Thursday that the US would "never give up" trying to secure the former US Marine's release. 

"Sadly, for totally illegitimate reasons, Russia is treating Paul's case different than Brittney's," he said.

Whelan was working as a corporate security officer at the time of his arrest in a Moscow hotel. Whelan's lawyer said Thursday that discussions about an exchange are "ongoing," Russia's Interfax news agency reported.

"Despite our ceaseless efforts, the Russian government has not yet been willing to bring a long overdue end to his wrongful detention. I wholeheartedly wish we could have brought Paul home today on the same plane with Brittney," US Secretary of State Antony Blinken said in a statement. 

The Biden administration said it let Whelan's family know in advance that he would not be released along with Griner.

wmr/aw (AP, Reuters, dpa, AFP)