By Guy Faulconbridge and Caleb Davis
LONDON (Reuters) - Russia said on Friday it hoped to clinch a prisoner swap with the United States to return convicted Russian weapons trafficker Viktor Bout, known as the "Merchant of Death", in an exchange that would likely include U.S. basketball star Brittney Griner.
Amid the deadliest war in Europe since World War Two, Russia and the United States are exploring a deal that could see imprisoned Americans including Griner return to the United States in exchange for Bout.
"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," Russian Deputy Foreign Minister Sergei Ryabkov was quoted as saying by Interfax.
"The Americans are showing some external activity, we are working professionally through a special channel designed for this," Ryabkov said. "Viktor Bout is among those who are being discussed, and we certainly count on a positive result."
For the two former Cold War foes, now grappling with the gravest confrontation since the 1962 Cuban Missile Crisis, the exchange would mark one of the more extraordinary prisoner swaps in their history.
The distinctly upbeat remarks from Ryabkov, the foreign ministry's point man for the Americas and arms control, contrast with previous statements from Moscow which have cautioned Washington against trying to engage in megaphone diplomacy over the prisoner swap.
The possible swap includes Griner, facing nine years behind bars in Russia after being convicted on drug charges, and Paul Whelan who is serving a 16-year sentence in Russia after being convicted of espionage charges that he denies.
Russia and the United States have discussed swapping Griner and Whelan, a former U.S. Marine, for Bout, but no deal has materialized amid heightened tensions over Russia's invasion of Ukraine.
The U.S. State Department on Friday said Washington has made a substantial offer that Moscow "has consistently failed to negotiate in good faith on."
"The Russian government's failure to seriously negotiate on these issues in the established channels, or any other channel for that matter, runs counter to its public statements. Ultimately, here, actions speak louder than words," State Department deputy spokesperson Vedant Patel told reporters.
BOUT FOR GRINER
Variously dubbed "the merchant of death" and "the sanctions buster" for his ability to get around arms embargoes, Bout was one of the world's most wanted men before his 2008 arrest on multiple charges related to arms trafficking.
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.
But in 2008, Bout was snared in an elaborate U.S. sting.
Bout was caught on camera agreeing to sell undercover U.S. agents posing as representatives of Colombia's leftist FARC guerrillas 100 surface-to-air missiles, which they would use to kill U.S. troops. Shortly afterwards, he was arrested by Thai police.
Bout was tried on the charges related to FARC, which he denied, and in 2012 was convicted and sentenced by a U.S. judge in New York to 25 years in prison, the minimum sentence possible.
Ever since, the Russian state has been keen to get him back.
Griner has been transferred to a penal colony in the Mordovia region, southeast of Moscow, her lawyers said on Thursday, confirming a Reuters report.
At her trial, Griner - who played basketball for a Russian team in the U.S. off-season - said she had used cannabis for relief from sports injuries but had not meant to break the law. She told the court she made an honest mistake by packing the cartridges in her luggage.