US basketball star Brittney Griner has been freed in a prisoner swap, a US official has said.

She had been imprisoned in Russia after being convicted in August and sentenced to nine years in prison.

Ms Griner was detained in February when customs agents said they found vape canisters containing cannabis oil in her luggage at Moscow’s Sheremetyevo Airport.

She was released in exchange for convicted Russian arms dealer Viktor Bout, who has been known as the “Merchant of Death”.

President Joe Biden says he has spoken to Ms Griner and that she is “safe” and “on her way home”.

The swap took place in Abu Dhabi airport, according to the Russian Foreign Ministry.

For almost two decades, Bout was one of the world’s most notorious arms dealers, selling weaponry to rogue states, rebel groups and murderous warlords in Africa, Asia, and South America.

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Ever since his capture in an elaborate US sting, the Russian state has been keen to bring him back.

Biden’s authorisation to release Bout underscores the escalating pressure that his administration has faced to bring Ms Griner, particularly after the recent resolution of her criminal case and her subsequent transfer to a penal colony.