Lawyers for US basketball star Brittney Griner has filed an appeal against her nine-year prison sentence for drugs possession, according to Russian news agencies.

Griner, a centre for Phoenix Mercury and a two-time Olympic gold medallist, was convicted on August 4.

She was arrested in February at Moscow’s Sheremetyevo Airport after vape canisters containing cannabis oil were found in her luggage.

Griner played for a women’s basketball team in Yekaterinburg during the WNBA off-season.

Lawyer Maria Blagovolina was quoted by Russian news agencies on Monday as saying the appeal was filed, but the grounds of the appeal were not clear.

Ms Blagovolina and co-counsel Alexander Boykov said after the conviction that the sentence was excessive and that in similar cases defendants had received an average sentence of about five years, with about a third of them granted parole.

Griner admitted she had the canisters in her luggage but said she had inadvertently packed them in haste and she had no criminal intent.

Her defence team presented written statements that she had been prescribed cannabis to treat pain.

Before her conviction, the US State Department declared Griner to be ‘‘wrongfully detained’’.

Secretary of state Antony Blinken took the unusual step of disclosing publicly in July that the US had made a ‘‘substantial proposal’’ to get Griner home, along with Paul Whelan, an American serving a 16-year sentence in Russia for espionage.

-AP