Brittney Griner freed in prisoner swap with Russian arms dealer

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, Sky News reports.

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".

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.

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