Yekaterinburg, Russia - A dual US-Russian citizen accused of donating around $50 to a pro-Ukrainian charity went on trial for treason in the Russian city of Yekaterinburg on Thursday, a regional court said.

Ksenia Karelina, a 32-year-old ballerina living and working in Los Angeles, was detained by police in Yekaterinburg in late January while on a trip to visit her family in Russia.

Prosecutors accused her of "proactively transferring funds to a Ukrainian organization, which the Ukrainian Armed Forces subsequently used to purchase tactical medicine, equipment, weapons and ammunition".

She donated around $50 to a New York-based Ukrainian charity in February 2022, shortly after Russia launched its military offensive, and now faces up to 20 years in prison if found guilty.

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Karelina smiled to reporters in court as she sat in the defendants' cage ahead of the hearing, video published by the regional court showed.

The court held the actual proceedings behind closed doors, as is typical for treason trials, and scheduled another hearing for August 7.

Karelina's partner has publicly petitioned for her release.

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.

Among other US nationals detained in Russia are reporters Evan Gershkovich and Alsu Kurmasheva, and former US marine Paul Whelan.

And on Wednesday, a court in Russia's far east jailed a US soldier for three years and nine months after convicting him for having threatened to kill his girlfriend and for stealing from her.

Moscow claims it has presented its ideas for a prisoner swap to the US and is waiting for a response.