(NEW YORK) -- A Russian court has denied the appeal of WNBA star Brittney Griner, who is facing nine years in a Russian prison on drug charges.
Griner appeared virtually at her appeal hearing on Tuesday and urged the court to reassess her sentence, saying that people found guilty of lesser crimes were given shorter sentences.
"I beg that the court takes in all of the stakes that was overlooked in the first court and reassess my sentence here," Griner said, apologizing for her "mistake" and saying that it has been "traumatic" to be away from her family.
Griner, a 31-year-old Houston native who plays professional basketball for the Phoenix Mercury, was detained on Feb. 17 at Sheremetyevo International Airport in Khimki as she returned to Russia to play during the WNBA's off-season after she was accused of having vape cartridges containing hashish oil, which is illegal in the country.
Griner pleaded guilty to drug charges in July, saying that the vape cartridges containing hashish oil were in her luggage mistakenly and that she had no "intention" of breaking Russian law.
Griner's agent, Lindsay Colas, called the appeal decision "disappointing, yet unsurprising," and one that "further validates the fact that she is being held hostage and is being used as a political pawn."
"Brittney Griner is being held by Russia simply because she is an American," Colas said in a statement. "We call on all people, fellow Americans, along with the global sports community, to unite in their support for [Griner] and President [Joe] Biden's efforts to do what is necessary to rescue her."
The U.S. national security adviser, Jake Sullivan, reiterated in a statement following the court's decision on Tuesday the Biden administration's commitment to securing Griner's freedom, calling the appeal hearing "another sham judicial proceeding."
"In recent weeks, the Biden-Harris Administration has continued to engage with Russia through every available channel and make every effort to bring home Brittney as well as to support and advocate for other Americans detained in Russia, including fellow wrongful detainee Paul Whelan," Sullivan said. "The President has demonstrated that he is willing to go to extraordinary lengths and make tough decisions to bring Americans home, as his Administration has done successfully from countries around the world. The Administration remains in regular touch with representatives of the families, and we continue to admire their courage in the face of these unimaginable circumstances."
Later Tuesday, Biden told reporters at an event while receiving a COVID-19 booster that "we are in constant contact with Russian authorities to get Brittney and others out and, so far, we've not been meeting with much positive response. But we're not stopping."
As the U.S. works to secure the basketball star's freedom, Griner's attorney told ABC News earlier this month that Griner is worried that she may not be released.
"Her being afraid of not being released is mostly connected to the negotiations, which we are not aware of at all," Griner's attorney Alexandr Boikov told ABC News on Oct. 13.
After being detained in Russia for more than five months, Griner was found guilty on drug charges in a Moscow-area court on Aug. 4 and was sentenced to nine years in prison. Her attorneys filed an appeal on Aug. 15.
"She is not very much hopeful for the appeal because the first court decision -- the verdict showed that the case is totally unjust even by present Russian standards, and we are not hoping for a big release, but of course we hope for the best," Boikov previously told ABC News.
The WNBA star turned 32 behind bars in Russia on Oct. 18 but she was able to spend a few hours with her lawyers, who relayed birthday messages to her, as well as speak on the phone with U.S. officials.
"Thank you everyone for fighting so hard to get me home. All the support and love are definitely helping me," Griner said through a message shared by her attorneys.
Brittney Griner found guilty in Russian drug trial, sentenced to 9 years in prison
The U.S. government classified Griner's case on May 3 as "wrongfully detained," meaning the U.S. will more aggressively work to negotiate her release even as the legal case against her plays out, the State Department has said.
Russia's invasion of neighboring Ukraine began one week after Griner was detained, and some officials have expressed concern that Americans jailed in Russia could be used as leverage in the ongoing war.
ABC News' Joseph Simonetti and Ben Gittleson contributed to this report.