President Joe Biden met Friday with relatives of basketball star Brittney Griner and fellow US citizen Paul Whelan, who are both imprisoned in Russia, as the US works to bring them home, the White House said.

In separate Oval Office meetings, Biden conferred with Whelan's sister, Elizabeth Whelan, and then Cherelle Griner, the wife of the Olympic gold medalist.

After the meetings the White House released a statement saying Biden "appreciated the opportunity to learn more about Brittney and Paul from those who love them most, and acknowledged that every minute they are being held is a minute too long."

The statement did not include any details about the status of talks with Russian authorities, but National Security Council spokesman John Kirby told reporters earlier in the day that "discussions are ongoing" to secure Griner's release.

"The president is not going to let up. He's confident that this is going to remain at the forefront of his mind and his team's mind," Kirby said.

Cherelle Griner, in a statement released by her wife's agent, thanked Biden for the meeting and his "administration's efforts to secure her release."

"I've felt every minute of the grueling seven months without her," she said.

In August, Moscow said it was ready to discuss a prisoner swap for Griner, sparking hopes of a rapid resolution.

Kirby said the Biden administration had made what he called a serious proposal but "they are not responding to our offer."

"These two individuals ought to be home already. Period," he added.

Griner was arrested at a Moscow airport in February, shortly before Russia's invasion of Ukraine, for possessing vape cartridges with a small amount of cannabis oil.

The 31-year-old, who was in Russia to play for the professional Yekaterinburg team during her off-season from the Phoenix Mercury, was charged with smuggling narcotics.

In early August she was sentenced to nine years in a penal colony.

Former US marine Whelan, 52, was arrested in December 2018 and accused by Russian security services of spying.

He was detained on a visit to Moscow to attend a wedding when he took a USB drive from an acquaintance, thinking it contained holiday photographs. He did not look at the contents of the drive, but his lawyer said it contained "state secrets."

The former security official at a vehicle parts company -- who also has British, Canadian and Irish passports -- was sentenced to 16 years on espionage charges in June 2020.