Russia said on Friday it was ready to discuss prisoner swaps with the United States through an existing diplomatic channel, a day a Russian court sentenced basketball star Brittney Griner to nine years in prison for a drugs offence.
Foreign Minister Sergei Lavrov said President Vladimir Putin and his US counterpart Joe Biden had previously agreed on a diplomatic channel that should be used to discuss such matters.
"We are ready to discuss this topic, but within the framework of the channel that was agreed upon by presidents Putin and Biden," Lavrov said during a visit to Cambodia.
"If the Americans decide to once again resort to public diplomacy..., that is their business and I would even say that it is their problem."
The Kremlin had previously warned the United States against turning to "megaphone diplomacy" in the case of Griner, saying it could only derail efforts to secure a potential swap.
Griner's sentence - which Biden called "unacceptable" - could pave the way for a prisoner swap that would include the 31-year-old athlete and a prolific Russian arms dealer serving a 25-year prison term in the United States.
The United States has already made what Secretary of State Antony Blinken called a "substantial offer" to secure the release of Americans detained in Russia, including Griner and former Marine Paul Whelan.
'A serious proposal'
White House national security spokesperson John Kirby said after Griner's sentencing that the United States had made Russia a serious proposal.
"We urge them to accept it," he said. "They should have accepted it weeks ago when we first made it."
Kirby did not provide further detail on the US proposal.
Washington has offered to exchange Russian arms trafficker Bout for Griner and Whelan, sources familiar with the situation have told Reuters.
Russia had tried to add convicted murderer Vadim Krasikov, imprisoned in Germany, to the proposed swap, a source familiar with the proceedings also told Reuters.
Griner, a two-time Olympic gold medalist and Women's National Basketball Association (WNBA) star, was arrested on Feb. 17 at Moscow's Sheremetyevo with vape cartridges containing hashish oil in her luggage.
The United States argued she was wrongly detained and being used as a political bargaining chip by Moscow. Russian officials dismissed the US claims, saying Griner had broken Russian law and should be judged accordingly.
Griner, who had been prescribed medical cannabis in the United States to relieve pain from chronic injuries, said she had made an honest mistake by inadvertently packing her vape cartridges as she rushed to make her flight.
She pled guilty to the changes against her but insisted that she did not intend to break Russian law.
Cannabis is illegal in Russia for both medicinal and recreational purposes.