Russian prosecutors on Thursday demanded US basketball star Brittney Griner be sentenced to nine and a half years in prison.

Griner, 31, was arrested in February for drug possession and smuggling after customs officials at Moscow airport found cannabis oil in her luggage.

Under Russian law, drug smuggling can carry a maximum of 10 years in prison.

Ahead of the verdict which is expected later on Thursday, Griner, who pleaded guilty to the charges last month, read an emotional statement to the court in which she asked for leniency.

"I never meant to hurt anybody, I never meant to put in jeopardy the Russian population, I never meant to break any laws here," Griner said.

"I made an honest mistake and I hope that in your ruling that it doesn't end my life here. I know everybody keeps talking about political pawn and politics, but I hope that that is far from this courtroom," she said.