US basketball player Brittney Griner has been moved to a penal colony in Russia, her lawyers said on Wednesday.
The jailed Olympian was reportedly transferred from a detention centre in Iksha, north of Moscow, last week.
"We do not have any information on her exact current location or her final destination,” a statement from her legal team read.
US Secretary of State Antony Blinken said in a statement on Wednesday the United States expects Russian authorities to provide its embassy officials with access to Griner and other Americans detained in Russia.
"We strongly protest the movement of Brittney Griner to a remote penal colony and the Russian government's use of wrongful detentions," Blinken said in a separate post on Twitter.
Griner was convicted of drug offences in August after Russian police said they found vape canisters containing cannabis oil in her luggage at Moscow’s Sheremetyevo Airport.
Griner has admitted that she had the canisters in her luggage but says she had no criminal intent and had been prescribed cannabis to treat pain.
"Every minute that Brittney Griner must endure wrongful detention in Russia is a minute too long," said White House Press Secretary Karine Jean-Pierre.
"As the [US] Administration continues to work tirelessly to secure her release, the President has ...[called on] her Russian captors to improve her treatment and the conditions she may be forced to endure in a penal colony," she added.
"As we have said before, the US Government made a significant offer to the Russians to resolve the current unacceptable and wrongful detentions of American citizens."
The two-time Olympic gold medalist was arrested amid heightened tensions between the US and Russia, just days before Russia invaded Ukraine. The US has said the case is politically motivated.
President Joe Biden said on Wednesday that he hopes Russian President Vladimir Putin will be more willing to negotiate the release of the WNBA star now that the US midterm elections are over.
US officials have for months tried to negotiate the release of Griner and another American jailed in Russia, Paul Whelan -- an American serving a 16-year sentence in Russia for espionage.