US-Russian citizen Ksenia Karelina was sentenced to 12 years in prison for "treason" by a Russian court on Thursday, after allegedly donating a little over $50 (€46) to a pro-Ukraine charity.

Karelina, a 32-year-old ballet dancer and spa worker living and working in Los Angeles, was detained by police in the Russian city of Yekaterinburg in late January while visiting family.

"The court found Ksenia Karelina guilty of high treason and sentenced her to 12 years' imprisonment in a general regime colony," the Sverdlovsk Regional Court in the Urals city of Yekaterinburg said.

Karelina stood in a glass defendant's cage wearing a white top and jeans as the verdict was read out, a video posted by the court showed.

She donated $51.80 to New York-based charity "Razom for Ukraine" shortly after Russia launched its full-scale military offensive in February 2022, US media outlets reported, citing her family and employer.

Russia's FSB security service accused her of collecting money that was "used to purchase tactical medical supplies, equipment, weapons and ammunition for the Ukrainian armed forces."

She pleaded guilty to the charges at a hearing last week, state media said.

Washington has accused Moscow of arresting its citizens on baseless charges to use them as bargaining chips to secure the release of Russians convicted abroad.

Karelina's sentencing comes just over two weeks after Russia freed US reporter Evan Gershkovich, former US marine Paul Whelan and 14 others in its biggest prisoner swap with the West since the Cold War.

Former prisoners released by Russia, US journalist Evan Gershkovich (C), former US marine Paul Whelan (C), and US-Russian journalist Alsu Kurmasheva (L) smile after their arrival in the US. Photo: AFP

On Wednesday, an American man accused of violence against a Russian law enforcement officer in Moscow was sentenced to 15 days in custody for "hooliganism".

'Wrongly accused'

Karelina's employer, the Ciel Spa at the SLS Hotel in Beverly Hills, wrote on Facebook in February that she had been "wrongly accused".

Her partner has also publicly petitioned for her release.

Karelina was first detained on 27 January while visiting family in the city of Yekaterinburg, almost a month after flying out to Russia, according to a Russian rights group.

Russian regional news agency URA.RU reported the charge was related to "swearing in a public place", an accusation she rejected in court, according to the Mediazona news outlet. 

FSB officers may have discovered she made the payment to the pro-Ukraine charity on her phone, but it was not clear how, according to Russian media outlets.

She was initially held for 14 days after being detained for "petty hooliganism" but was never released, as authorities charged her with "treason" while she was in custody.

Russia often arrests foreigners on minor charges before accusing them of more serious offences like treason or espionage.