Russian authorities said on Friday that the government would be willing to perform a prisoner swap with the U.S.
The U.S. and Russia discussed a trade between convicted weapons trafficker Victor Bout who was arrested in 2008, and American Brittney Griner who was recently sent to a Russian penal colony.
Bout, known as "the merchant of death" and as a "sanctions buster" was among the world's most wanted men before he was arrested.
His client list is said to have included warlords in Asia and Africa and rogue states.
Experts believe that Bout has ties to the Russian intelligence service and Moscow has long sought to secure his release from a jail in the United States, Reuters reported.
The exchange is likely to include U.S. basketball player Brittney Griner who was detained in February for allegedly being in possession of cannabis oil, which is illegal in Russia, and was found in her luggage after she arrived at a Moscow airport on a flight from New York City.
She was sentenced on Aug. 4 to nine years in prison after a trial that lasted weeks.