U.S. basketball star Brittney Griner, who was freed from a Russian penal colony in a prisoner exchange last year, has urged the Biden administration to keep using “every tool possible” to win the release of a U.S. reporter accused of spying in Russia.

Griner and her wife Cherelle said on Instagram that “our hearts are filled with great concern” for Evan Gershkovich, the journalist arrested by Russia’s FSB security service last week in the Urals city of Yekaterinburg.

The Kremlin says Gershkovich was using journalism as a cover for spying activity – something his newspaper, the Wall Street Journal, has vehemently denied.

Russia has not made public any evidence to support the charges, under which Gershkovich faces up to 20 years in jail. The White House has described the accusations as “ridiculous” and President Joe Biden has called on Moscow to release him.

The Griners said they were grateful for Biden’s “deep commitment to rescue Americans”. They cited the cases of aid worker Jeff Woodke, freed last month after being kidnapped for more than six years in West Africa, and Paul Rusesabagina, a permanent U.S. resident who returned home last week after being released from prison in Rwanda.

The couple added, “we call on all of our supporters to both celebrate the wins and encourage the administration to continue to use every tool possible to bring Evan and all wrongfully detained Americans home”.

Brittney Griner, a WNBA star and double Olympic gold medallist who played for a Russian team in the off-season, was arrested at a Moscow airport one week before Russia invaded Ukraine last year.

She was found with vape cartridges containing cannabis oil in her luggage and sentenced to nine years in a penal colony after being convicted on drug smuggling and possession charges, a verdict that Biden called “unacceptable”.

She was freed in December in exchange for Viktor Bout, a Russian arms dealer who spent 14 years in jail in the United States for arms trafficking, money laundering and conspiring to kill Americans.