By Guy Faulconbridge and Mark Trevelyan
LONDON (Reuters) -Russia said on Thursday there was no deal yet with the United States on swapping detained U.S. basketball star Brittney Griner and a former Marine for an imprisoned Russian called by American prosecutors one of the world's most prolific arms dealers.
Secretary of State Antony Blinken said on Wednesday the United States has made a "substantial offer" to Russia to release American citizens held in Russia. A source said that Washington was willing to exchange convicted arms trafficker Viktor Bout, known as the "Merchant of Death."
Kremlin spokesman Dmitry Peskov expressed surprise at the public remarks from Blinken. Russia has cautioned the United States that such discussions are best conducted in private.
"So far, there are no agreements in this area," Peskov told reporters in Moscow. "When discussing such topics, you don't conduct information attacks."
Russian foreign ministry spokeswoman Maria Zakharova indicated that talks on prisoner exchanges had been going on for some time but without a result.
U.S. President Joe Biden has come under growing pressure in recent months from the families of American hostages and detainees who have urged him to intervene personally to bring home their loved ones. This might explain the U.S. decision to make the negotiations public. The U.S. offer was made weeks ago.
"The fact that now, several weeks later, we are where we are, I think you can read into that as being a reflection of the fact that this has not moved to the extent we would like," State Department spokesperson Ned Price told a daily briefing.
Price added that Russia has acknowledged a U.S. request to have a phone call between Blinken and Russian Foreign Minister Sergei Lavrov and that the United States still is expecting the call to take place in the coming days.
The Interfax news agency cited Zakharova as saying Lavrov has a busy schedule and will address the request when he has time.
For the two former Cold War foes, now grappling with the worst relations in a generation due to Russia's invasion of Ukraine, the exchange would mark one of the more extraordinary prisoner swaps in their history.
Griner, a two-time Olympic gold medallist and a Women's National Basketball Association (WNBA) star, was detained at Moscow's Sheremetyevo airport on Feb. 17 with vape cartridges containing hashish oil in her luggage.
Griner has pleaded guilty to the charges against her but has denied that she intended to break Russian law.
"I do plead guilty because of the actions that have happened but again, I did not intend to smuggle or bring any substance into Russia," Griner told a Russian court on Wednesday.
Griner said she still did not understand how the vape cartridges containing hashish oil could have ended up in her luggage. The next hearing is set for Aug. 2. Griner is unlikely to be swapped until there is a verdict, which could happen by mid-August, her lawyers said.
"From a legal point of view, an exchange is only possible after a court verdict," Griner's lawyer in Russia, Maria Blagovolina, said in a statement.
The other American, former Marine Paul Whelan, who holds American, British, Canadian and Irish passports, was sentenced in 2020 to 16 years in jail after being convicted of spying.
Russia said Whelan was caught with classified information in a Moscow hotel room where agents from the Federal Security Service detained him on Dec. 28, 2018. He denies that he committed espionage.
Bout, a former Soviet military translator who the United States has said became one of the world's preeminent arms dealers, is serving a 25-year prison sentence. He has proclaimed his innocence.
The subject of the book "Merchant of Death" and the inspiration for actor Nicolas Cage's character in the 2005 movie "Lord of War," Bout supplied military-grade weaponry to conflict zones around the world, according to U.S. prosecutors.
Bout was arrested in Bangkok in 2008 in a sting operation in which U.S. Drug Enforcement Administration informants posed as representatives of the Colombian rebel group Revolutionary Armed Forces of Colombia, or FARC.
Russia has said that the case against him was fabricated by U.S. special services.
A jury in 2011 found Bout guilty on charges including conspiracy to kill U.S. nationals and officers and conspiring to acquire and use anti-aircraft missiles. He was sentenced in 2012 to 25 years in prison.
(Reporting by Reuters; additional reporting by Humeyra Pamuk and Simon Lewis in Washington and David Ljunggren in Ottawa, editing by Guy Faulconbridge and Mark Porter)