KHIMKI, Russia (AP) — US basketball star Brittney Griner was convicted Thursday in Russia of drug possession and sentenced to nine years in prison following a politically charged trial that came amid soaring tensions between Moscow and Washington over Ukraine and could lead to a high-stakes prisoner exchange between the two world powers.

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. The judge also fined 1 million rubles (about $16,700) fine.

US President Joe Biden denounced the verdict and sentence as “unacceptable.”

“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.

Earlier in the session, with a conviction all but certain, an emotional Griner made a final appeal to the court for leniency. She said she had no intention to break the law by bringing vape cartridges with cannabis oil when she flew to Moscow in February to play basketball in the city of Yekaterinburg.

“I want to apologise to my teammates, my club, my fans and the city of (Yekaterinburg) for my mistake that I made and the embarrassment that I brought on them,” Griner said, her voice cracking. “I want to also apologize to my parents, my siblings, the Phoenix Mercury organization back at home, the amazing women of the WNBA, and my amazing spouse back at home.”

Prosecutor Nikolai Vlasenko insisted that Griner packed the cannabis oil deliberately, and he asked the court to hand Briner a fine of 1 million rubles (about $16,700) in addition to the prison sentence.

Lawyers for the Phoenix Mercury center and two-time Olympic gold medalist have sought to bolster Griner’s contention that she had no criminal intent and that the canisters ended up in her luggage by mistake. They presented character witnesses from the Yekaterinburg team that she plays for in the WNBA offseason and written testimony from a doctor who said he prescribed her cannabis for pain treatment from injuries sustained in her basketball career.

Before her trial began in July, the State Department designated her as “wrongfully detained,” moving her case under the supervision of its special presidential envoy for hostage affairs, effectively the government’s chief hostage negotiator.

Then last week, in an extraordinary move, Blinken spoke to Russian Foreign Minister Sergey Lavrov, urging him to accept a deal under which Griner and Whelan would go free.

The Lavrov-Blinken call marked the highest-level known contact between Washington and Moscow since Russia sent troops into Ukraine more than five months ago. The direct outreach over Griner is at odds with U.S. efforts to isolate the Kremlin.

People familiar with the proposal say it envisions trading Griner and Whelan for the notorious arms trader Viktor Bout, who is serving a prison sentence in the United States. It underlines the public pressure that the White House has faced to get Griner released.

White House Press Secretary Karine Jean-Pierre said Monday that Russia has made a “bad faith” response to the US government’s offer, a counteroffer that American officials don’t regard as serious. She declined to elaborate.

Russian officials have scoffed at US statements about the case, saying they show a disrespect for Russian law. They remained poker-faced, urging Washington to discuss the issue through “quiet diplomacy without releases of speculative information.”