Russia said on Friday it was ready to discuss a prisoner swap with Washington at the presidential level, a day after the drug conviction of US basketball star Brittney Griner.

Despite tensions soaring between Russia and the US since the launch of Moscow's military intervention in Ukraine, the former Cold War rivals appeared to be edging closer to a new prisoner exchange.

The White House has urged Russia to accept its offer of a deal for the release of Griner and former US Marine Paul Whelan, who was sentenced to 16 years in prison on espionage charges.

Russia's Foreign Minister Sergei Lavrov on Friday said Russia was willing to discuss the matter.

“We are ready to discuss this subject, but only within the framework of the (communication) channel established by presidents Putin and Biden,” Lavrov told a press conference on a visit to Cambodia.

“There is a special channel established by the presidents and despite certain public declarations, it is still functional,” he added.

WNBA player Griner was on Thursday sentenced to nine years in a Russian penal colony and ordered to pay a fine of one million rubles ($16,590) for possessing and smuggling narcotics.

The two-time Olympic basketball gold medallist and Women's NBA champion was detained at a Moscow airport in February after she was found carrying vape cartridges with cannabis oil in her luggage.

The Phoenix Mercury player was coming to Russia to play club basketball with UMMC Ekaterinburg during the US off-season — a common path for American stars seeking additional income.

Griner pleaded guilty to the charges, but said she did not intend to break the law or use the banned substance in Russia.

'Honest mistake'

“I want the court to understand it was an honest mistake that I made while rushing, under stress, trying to recover from post-Covid and just trying to get back to my team,” Griner said in her final statement before the verdict.

Griner had testified that she had permission from a US doctor to use medicinal cannabis to relieve pain from her many injuries, and had never failed a drug test.

The use of medical marijuana is not allowed in Russia.

Griner's legal team said they plan to appeal the “unreasonable” verdict.

US President Joe Biden called Griner's conviction “unacceptable” and said Washington would “work tirelessly” to secure her release.

US Secretary of State Antony Blinken said last week that Washington had made a “substantial proposal” to Moscow to free Griner and Whelan.

A prisoner swap was discussed during a call between Blinken and Lavrov last Friday.

The highest-profile Russian prisoner in the United States is Victor Bout, a 55-year-old arms trafficker, dubbed the “Merchant of Death”, who is serving 25 years in jail.

There is no official confirmation that Washington has offered to exchange him.

Bout's wife Alla on Friday expressed her sympathies to Griner's family, saying she hoped her husband and the US athlete will be able to return home.

“Sympathy has no citizenship and nationality, it is a universal human emotion,” she told Russian news agency RIA Novosti, expressing hope that Russia and the US would “come to an agreement”.

Russia and the United States have already conducted one prisoner swap since the start of Moscow's Ukraine offensive.

In April, Washington exchanged former US Marine Trevor Reed for convicted drug smuggler Konstantin Yaroshenko.