KHIMKI, Russia (AP) — Brittney Griner was back in court on Tuesday for her trial for cannabis possession amid U.S. diplomatic efforts to secure her release.

If convicted, the WNBA star and two-time Olympic gold medalist could face 10 years in prison. As her trial progressed, the Biden administration has faced growing public pressure to get her released.

In an extraordinary move, Secretary of State Antony Blinken last week spoke to his Russian counterpart, Sergey Lavrov, urging him to accept a deal under which Griner and Paul Whelan, an American imprisoned in Russia on an espionage conviction, 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 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. It underlines the public pressure that the White House has faced to get Griner released.

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

Griner has acknowledged there were vape canisters containing cannabis oil in her luggage when she was arrested at a Moscow airport in February. But she insisted that she had no criminal intent and that the canisters ended up in her luggage because she was packing hastily. Griner played for a Russian women’s basketball team in the WNBA off-season.

To bolster her case, her defense lawyers presented testimony from doctors that she was prescribed cannabis as a treatment for pain. Medical marijuana treatment is not legal in Russia.

While judges have leeway to consider mitigating factors under Russian law, acquittals are rare and account for less than 1% of cases in Russian criminal prosecutions.

A conviction, however, could potentially pave the way for Griner’s exchange as Russian officials said it could only happen after the judicial process is completed.

Tom Firestone, a Washington attorney who formerly served as a legal adviser at the U.S. Embassy in Moscow, said Griner could be handed a tough sentence as a way for Russians “to maximize their leverage in negotiations.” He told The Associated Press that Russia “may want to let this play out a little bit longer and try to extract more concessions.”

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