WASHINGTON (Reuters) – U.S. Secretary of State Antony Blinken has spoken with Brittney Griner’s wife, assuring her that securing the release of the American professional basketball player detained in Russia is a top priority for the Biden administration, a senior State Department official said Tuesday.

Griner, a two-time Olympic gold medalist, was arrested in February at Moscow’s Sheremetyevo airport, allegedly in possession of cannabis-infused vaporizer cartridges.

The Russian customs service said at the time that the alleged offence could carry a prison term of five to 10 years. The U.S. State Department this month said the 31-year-old was wrongfully detained, and has assigned diplomats to work for her release.

The official said Blinken told Cherelle Griner on Saturday that the United States is working day and night on the case, which has his full attention.

A Russian court on Friday extended Griner’s pretrial detention by one month, her lawyer told Reuters.

Washington and Moscow have kept diplomatic channels open since Russia’s Feb. 24 invasion of Ukraine, despite the dire state of bilateral relations.

They agreed on a prisoner swap last month in which U.S. Marine veteran Trevor Reed was freed from prison in Russia, where he had been serving a nine-year sentence on assault charges.

He was exchanged for Konstantin Yaroshenko, a Russian pilot who had been serving a 20-year sentence in the United States after being convicted of drug trafficking.

Russia continues to hold Paul Whelan, another U.S. Marine veteran who was sentenced to 16 years in prison for espionage in 2020.