Lawyers acting on behalf of American WNBA star and two-time Olympic gold medalist Brittney Griner have lodged an appeal against the 31-year-old's nine-year prison sentence in Russia.

Griner, who plays for Russian team UMMC Yekaterinburg, was arrested at Moscow Sheremetyevo airport on February 17 after officials discovered e-cigarette cartridges containing hashish oil in her luggage.

Griner had been prescribed the drug by doctors in the United States for the alleviation of injury pain – but cannabis is illegal in Russia.

Although Griner pleaded guilty, she insisted that she did not intentionally break Russian law. But the Moscow court did not accept any mitigating circumstances when handing down its ruling, which also included a fine of 1 million roubles (€16,000 / $16,320) .

Griner's lawyer, Maria Blagovolina, confirmed to Reuters on Monday that her client would appeal her sentence.

Prisoner swap possible

Meanwhile, the possibility of a prisoner swap between Russia and the United States remains an option.

The US has offered to exchange Viktor Bout, a Russian arms dealer currently serving a 25-year prison sentence in the US, for Griner – plus Paul Whelan, a former US soldier also currently detained in Russia.

Moscow, however, would also like Vadim Krasikov, a Russian secret service officer currently in jail in Germany for the murder of a Georgian secret service officer in Berlin, to be part of any exchange.

"This quite sensitive issue of the swap of convicted Russian and US citizens is being discussed through the channels defined by our presidents," Alexander Darchiev, director of the Russian foreign office's North America department, told Russian state news agency TASS on Sunday.

"The 'quiet diplomacy' continues, it should bear fruit, if, of course, Washington will strictly follow it without slipping into propaganda," he added. 

US diplomat 'optimistic'

Earlier this month, former US diplomat Bill Richardson, who has been involved in freeing several US citizens detained abroad, said he was "optimistic" that an exchange was possible.

There will be a "two-for-two prisoner swap," he told US network ABC last week, adding however that he was only indirectly involved with any negotiations.

The diplomacy is taking place against the backdrop of heightened tensions due in part to US support for Ukraine amid Russia's ongoing war of aggression there.

mf/wmr (AP/AFP)