Griner, 31, a Phoenix Mercury player playing in the offseason of the WNBA in Russia, was arrested at a Moscow airport on February 17.
Russian authorities accused her of smuggling large quantities of a narcotic, a crime punishable by up to 10 years in prison.
Griner is currently being held in a pre-trial detention center north of Moscow. According to her lawyer, her detention has been extended by six months pending the conclusion of the trial.
Earlier this week, US National Security Advisor Jake Sullivan reiterated that Griner “is wrongfully and wrongly imprisoned, and we have made that clear as an official statement by the US government.”
US Embassy Chargé d’Affaires Elizabeth Rood was also seen Friday arriving for Griner’s court hearing.
No verdict is expected on the first day of her trial, which is taking place in the Khimki City Court outside the Russian capital.
Griner’s supporters have expressed concern that the basketball star could be used as a political pawn amid rising tensions over Russia’s invasion of Ukraine.
Her detention, which has been repeatedly extended, has sparked a wave of support from dozens of organizations across the US, which have joined Griner’s wife, Cherelle, in urging President Joe Biden to strike an exchange deal with Russian authorities to release Griner and her to bring home safely as soon as possible.
Speaking to reporters from Air Force One earlier this week, Sullivan declined to detail U.S. efforts to resolve Griner’s case, citing the “sensitive matter” but claiming that the Biden administration “actively engaged”.
Griner was named an honorary starter for the WNBA All-Star Game last week, with the All-Star Game scheduled to take place in Chicago on July 10th. Her confinement is still “tough on our team,” Phoenix Mercury head coach Vanessa Nygaard told reporters ahead of Monday’s team’s game against Indiana Fever.
She expressed hope that Griner will return home soon and that President Biden will “take the steps to ensure she comes home.”