US basketball star Brittney Griner was on Thursday convicted in Russia of drug possession and smuggling and was sentenced to nine years in prison in a politically charged case that could lead to a high-stakes prisoner exchange between Washington and Moscow.

The 31-year-old Griner, a two-time US Olympic champion and a eight-time all-star with the WNBA’s Phoenix Mercury, listened with a blank expression as an interpreter translated the verdict by Judge Anna Sotnikova, but her lawyers said later she was “very upset.” Griner also was fined 1 million rubles (about $16,700).

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US President Joe Biden denounced as “unacceptable” the verdict and sentence, which came amid soaring tensions between the US and Russia over Ukraine.

“I call on Russia to release her immediately so she can be with her wife, loved ones, friends, and teammates,” Biden said, adding that he would continue to work to bring home Griner and Paul Whelan, an American imprisoned in Russia on an espionage conviction.

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Outside court, the US Embassy’s charge d’affaires Elizabeth Rood called the outcome “a miscarriage of justice.”

Griner, recognized as one of the greatest players in WNBA history, has been detained since Feb. 17 after police said they found vape cartridges containing cannabis oil in her luggage upon landing at Moscow’s Sheremetyevo Airport. She was returning to Russia, where she has competed since 2014.

As she was led out of court, Griner said, “I love my family.”

The nine-year sentence was close to the maximum of 10 years that Griner had faced under the charges. Most Russians possessing small quantities of drugs get at most five years in prison, lawyers said.

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Defense attorney Maria Blagovolina told reporters later that Griner was “very upset, very stressed. She can hardly talk. It’s a difficult time for her.”

Before the unusually swift verdict was reached, an emotional Griner apologised to her family, teammates and the Russian city of Yekaterinburg, where she plays in the WNBA offseason, “for my mistake that I made and the embarrassment that I brought on them.”

With her voice cracking, she added, “I hope in your ruling it does not end my life.”

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Under Russian law, Griner has 10 days to appeal, and her lawyers say they expect a hearing in Moscow regional court next week. Asked if Griner could ask for pardon from President Vladimir Putin, Blagovolina said they would consider every possibility, but the lawyers said they were not part of any discussions about a prisoner swap.

A conviction is usually a prerequisite to arranging a prisoner exchange and also allows Griner to apply for a presidential pardon. Deputy Foreign Minister Sergei Ryabkov said last month that the “necessary judicial procedures” must be completed before any other steps can be taken.