Washington: US basketball star Brittney Griner has been released in a prisoner swap with Russia and is now in US custody, President Joe Biden said on Thursday.

The Russian foreign ministry said it traded Griner for Russian citizen Viktor Bout, a former arms dealer. The swap occurred at the Abu Dhabi airport in the United Arab Emirates, Russian news agencies said.

"She is safe. She is on a plane. She is on her way home," Biden said in a tweet.

Biden and Vice President Kamala Harris spoke by phone with Griner from the Oval Office, a US official said, adding that the call included Griner's wife, Cherelle. The White House released a photo of the telephone call.

Biden was set to make remarks at 8.30 am (1330 GMT), the White House said.

Griner, 32, a star of the Women's National Basketball Association's Phoenix Mercury, was arrested on February 17. Talks to secure her release were complicated by Russia's February 24 invasion of Ukraine and the subsequent deep souring of ties between Washington and Moscow.

A two-time Olympic gold medallist, Griner was arrested at a Moscow airport when vape cartridges containing cannabis oil, which is banned in Russia, were found in her luggage.

She was sentenced on August 4 to nine years in a penal colony on charges of possessing and smuggling drugs. She had pleaded guilty, but said she had made an "honest mistake" and had not meant to break the law.

Last month she was taken to a penal colony in the Russian region of Mordovia to serve her prison sentence.

Variously dubbed "the merchant of death" and "the sanctions buster" for his ability to get around arms embargoes, Bout, 55, was one of the world’s most wanted men before his arrest.

For almost two decades, Bout became the world’s most notorious arms dealer, selling weaponry to rogue states, rebel groups and murderous warlords in Africa, Asia and South America. For experts on the Russian security services, Moscow's lasting interest in Bout hints strongly at Russian intelligence ties.