Brittney Griner freed from Russian prison in exchange for Viktor Bout

But the president expressed regret the deal did not include Paul Whelan, a Michigan corporate security executive jailed since December 2018 on espionage charges his family and the US government deny.

The second such exchange in eight months, following the freeing of Trevor Reed in April, procured the release of the most prominent American detained abroad.

The Russian foreign ministry confirmed to state media that Griner had been exchanged for Bout in a secret swap in Abu Dhabi but did not give more details.

Griner is a two-time Olympic gold medalist whose imprisonment on drug charges brought unprecedented attention to the population of wrongful detainees. She was arrested in February, convicted in August and sentenced to nine years in a Russian penal colony.

Whelan himself spoke to CNN from Russia.

After months of negotiations, Biden said in November he was hopeful. A top Russian official said last week a deal was possible before the end of the year. Even so, that the deal was a one-for-one swap was a surprise given US officials had for months expressed determination to bring home Griner and Whelan.

But the detention of one of the greatest players in WNBA history contributed to a swirl of unprecedented public attention for an individual detainee case.

The release followed months of negotiations involving Bill Richardson, the former US ambassador to the United Nations, and his top deputy, Mickey Bergman. Joint mediation between United Arab Emirates and Saudi Arabia also played a role, the countries said on Thursday.

In May, the US state department designated her as unlawfully detained. A separate trade, the marines veteran Reed for Konstantin Yaroshenko, a Russian pilot convicted in a cocaine-trafficking conspiracy, spurred hope of more exchanges.

The Associated Press contributed reporting