KHIMKI, Aug 4 (AFP) - A Russian court on Thursday (Aug 4) sentenced US basketball star Brittney Griner to nine years in prison over drug smuggling as US President Joe Biden called the ruling "unacceptable".

The court "found the defendant guilty" of smuggling and possessing "a significant amount of narcotics", judge Anna Sotnikova told a court in the town of Khimki just outside Moscow.

Sotnikova sentenced Griner, 31, to nine years in prison and said she would also have to pay a fine of one million rubles (US$16,590).

US President Joe Biden immediately released a statement, calling the Russian court's sentencing of Griner "unacceptable".

"Russia is wrongfully detaining Brittney. It's unacceptable and I call on Russia to release her immediately so she can be with her wife, loved ones, friends and teammates," Biden said in the statement.

The US president reiterated that he would "work tirelessly and pursue every possible avenue" to repatriate Griner.

Griner's trial accelerated in recent days as the United States and Russia discuss a potential prisoner swap that could involve the basketball star.

The 2.06m star was detained at a Moscow airport in February after she was found carrying vape cartridges with cannabis oil in her luggage. The arrest came just days before Moscow launched its military intervention in Ukraine.

Prosecutors had earlier requested the two-time Olympic basketball gold medallist and Women's NBA champion be sentenced to nine and a half years in prison on drug smuggling charges.

Griner's trial came with tensions soaring between Moscow and Washington over Russia's military intervention in Ukraine that has sparked international condemnation and a litany of Western sanctions.

"I made an honest mistake and I hope that your ruling doesn't end my life here," Griner said earlier Thursday.

"I want the court to understand it was an honest mistake that I made while rushing, under stress, trying to recover from post-Covid and just trying to get back to my team."

Griner pleaded guilty to the charges, but said she did not intend to break the law or use the banned substance in Russia.

Her defence team said they were "very disappointed" by the verdict and would appeal.

"The court completely ignored all the evidence of the defence, and most importantly, the guilty plea," lawyers Maria Blagovolina and Alexander Boykov said in a statement.

"The verdict is absolutely unreasonable. We will certainly file an appeal."

Prosecutor Nikolay Vlasenko had requested a prison sentence of nine years and six months for Griner, requesting a term just short of the maximum punishment of 10 years.

Vlasenko said Griner "deliberately" proceeded through the green corridor at customs and stated she had nothing to declare "in order to conceal" the substance.

Earlier in the day Griner walked into the courtroom in handcuffs, escorted by several law enforcement officers and a police dog.

Standing inside a cage for defendants before the start of the hearing, she held up a photo of herself with teammates from the Russian club she plays for.