The United States made an offer to Russia for the release of Britney Griner

Britney Griner, an American basketball star detained in Russia on drug possession charges, said Wednesday in a courtroom that she has been thrown into a convoluted judicial system with little to no explanation of what is going on or what she can do to try to defend herself.

Mrs. Griner said she arrived in Russia after a grueling 13-hour flight — and shortly after recovering from Covid — and found herself under interrogation, where much of what was said remained untranslated. She said she was also told to sign papers without explaining what it was.

It was her first court testimony about an arrest in a case that has taken on enormous significance because of the war in Ukraine.

When Ms. Griner arrived at the hearing in a long-sleeved T-shirt. wrists cuffed in front of herand flanked by a group of Russian security agents, some of whom were wearing bulletproof vests and their faces covered by balaclavas.

Russian authorities detained Mrs. Griner, 31, a two-time Olympian who plays for the Phoenix Mercury, about a week before President Vladimir Putin’s forces invaded Ukraine in February. She was accused of having two cartridges of hash oil in her luggage when she arrived at an airport near Moscow on her way to Yekaterinburg, where she plays for the WNBA team during the off-season.

Russia is not publicize her detention until the invasion began.

Earlier this month Mr. Grinner pleaded guilty, stating that she had inadvertently smuggled the banned substance into Russia because she packed in a hurry. In the Russian legal system, an admission of guilt does not end a trial; Lawyers for Mr. Griner, who faces a 10-year sentence, expect it to last until August.

Mrs. Griner’s lawyers hope her guilty plea will make the trial more lenient, but experts say her greatest hope is that the Biden administration will find a way to trade her for a high-ranking Russian detained by the United States.

On Wednesday, Secretary of State Anthony J. Blinken said the United States “submitted a substantial proposal a few weeks ago” to achieve liberation of Mr. Griner and Paul Whelan, a former Marine sentenced last year to 16 years in prison on charges of espionage. He declined to discuss the details of the proposal.

A source briefed on the talks said the United States offered to trade imprisoned Russian arms dealer Viktor Bout, for Miss. Griner and Mr. Whelan, and that President Biden, who was under increasing political pressure to free Americans, supported the proposal.

Testifying from a closed witness stand on Wednesday, Ms. Griner, one of her lawyers, Alexander Boikov of the Moscow Legal Center, said she was taken aside during a baggage check at Moscow’s Sheremetyevo Airport.

Mrs. Griner testified that during her detention she was ordered to sign documents without explaining their meaning. And Mr. Boikov said that the interpreter provided to Ms. Griner after the arrest translated “almost nothing” and that she was held for 16 hours before a lawyer came to her aid.

Maria Blagovolina, partner at the Rybalkin, Gortsunyan, Dyakin and Partners law firm, which also represents the interests of Ms. Griner stated this. her client told the court that she had “a doctor’s prescription for medical marijuana.”

“She emphasized that she never planned to bring it to Russia and use it,” she said. Blagovolina said.