US basketball star Brittney Griner could be released as part of a swap deal for a convicted arms trafficker known as the “Merchant of Death”.
The Olympic gold medallist was sentenced in August to nine years for possessing and smuggling drugs after cannabis oil was found in her luggage at Moscow’s Sheremetyevo Airport.
Speaking about the possibility of a prisoner swap, Mr Ryabkov said: “I want to hope that the prospect not only remains but is being strengthened, and that the moment will come when we will get a concrete agreement.
"The Americans are showing some external activity, we are working professionally through a special channel designed for this.
“Viktor Bout is among those who are being discussed, and we certainly count on a positive result.”
It comes after Ms Griner’s lawyers revealed she had been sent to a penal colony to serve her sentence.
US officials have for months tried to negotiate her release without success.
President Joe Biden said last week that he hopes Russian President Vladimir Putin will be more willing to negotiate her release in the near future.
“My hope is that now that the [midterm] election is over, that Mr Putin will be able to discuss with us and be willing to talk more seriously about a prisoner exchange,” Mr Biden said.
Six months ago, Mr Biden agreed to swap Konstantin Yaroshenko, a Russian pilot jailed on drugs charges, for Trevor Reed, an American held by Russia.
Ms Griner has apologised for what she said was an honest mistake.
She has claimed that she used medical cannabis to relieve the pain from a series of injuries. Both recreational and medicinal uses are prohibited in Russia.