The judge in a hearing near Moscow decided only to slightly modify the sentence, with pre-trial detention now taken into account.

Each day in custody since Griner's arrest on February 17 and before her conviction will count as 1.5 days toward her jail sentence.

Griner and her lawyers had asked the court for acquittal, or at least a reduction in her sentence, which they have argued is disproportionate to the offence and against Russian judicial practice.

The state prosecutor labelled the punishment as "fair".

The American basketball player apologised for making an "honest mistake" during the appeal hearing, where she appeared via videolink from a detention centre in Novoye Grishino.

Griner has maintained she accidently brought vape cannisters containing hashish oil into Russia after packing in a hurry.

The 32-year-old wore a lumberjack shirt over a hooded top and said in a statement read out in court that she "did not intend to do this", but suggested she understood the charges.

Griner added she hoped her guilty plea would be considered, and the sentence would be reduced following a "stressful" and "traumatic" time in prison.

Alexander Boykov, one of Griner's attorneys, told the court: "No judge, hand on heart, will honestly say that Griner's nine-year sentence is in line with Russian criminal law."

The lawyer recited several examples of what they said were procedural flaws in Griner's conviction and asked for an acquittal, adding that "if the court wants to punish her, [it should] give her a new, 'fair' verdict and mitigate the punishment."

The Phoenix Mercury star is now expected to serve her sentence in a penal colony.

Griner pleaded guilty to charges of drug possession last month after she was detained at Moscow's Sheremetyevo Airport.

The United States considers Griner "wrongly detained" and Elizabeth Rood, who is the charge d'affaires at the US Embassy in Moscow and attended the hearing, called the sentence "excessive and disproportionate".

Negotiations over a prisoner swap to facilitate her release have been ongoing but attempts have been complicated with relations between the United States and Russia collapsing following the invasion of Ukraine.

US President Joe Biden, who met with Griner's wife in September, has said he is willing to meet Vladimir Putin, his Russian counterpart, to discuss the basketball player's release at next month's G20 Summit in Indonesia.

US Secretary of State Antony Blinken claimed in August that the country had sent Russia a "substantial proposal" widely reported to centre on exchanging convicted arms trafficker Viktor Bout, who is Russian, for Griner and Paul Whelan, a US citizen imprisoned in Russia on an espionage conviction.

White House national security adviser Jake Sullivan rebuked today's hearing in a statement and reaffirmed Biden's commitment to freeing both Griner and Whelan.

"We are aware of the news out of Russia that Brittney Griner will continue to be wrongfully detained under intolerable circumstances after having to undergo another sham judicial proceeding today," he said.

"President Biden has been very clear that Brittney should be released immediately.

"In recent weeks, the Biden-Harris Administration has continued to engage with Russia through every available channel and make every effort to bring home Brittney as well as to support and advocate for other Americans detained in Russia, including fellow detainee Paul Whelan.

"The President has demonstrated that he is willing to go to extraordinary lengths and make tough decisions to bring Americans home, as his Administration has done successfully from countries around the world.

"The Administration remains in regular touch with representatives of the families, and we continue to admire their courage in the face of these unimaginable circumstances."

The Women's National Basketball Players Association (WNBPA) has also asked the International Basketball Federation(FIBA) and the worldwide sporting community to support Griner, insisting she is being held "hostage".

"Brittney has repeatedly taken responsibility and made clear that she never intended to break Russian laws," the WNBPA said.

"While their legal system is very different from ours, there is no doubt that the original sentence she received was extreme, even for the Russian legal system.

"This appeal is further verification that BG is not just wrongfully detained - she is very clearly a hostage."

It added: "We strongly encourage leadership at FIBA, and across the entire global sport community to voice their support for BG and join our campaign with a daily public call to action.

"No athlete should be used as a political pawn."

Griner won Olympic gold medals at Rio 2016 and Tokyo 2020.

She also helped the US win Women's Basketball World Cup titles in 2014 and 2018, but was absent when the Americans won the event again in Australia this month because of her detainment.