Ksenia Karelina, who was born in Russia but had built a new life as an aesthetician at a Los Angeles spa after immigrating to the United States over a decade ago, faces a sentence of 12 years to life in prison if found guilty.

Her trial will be held behind closed doors, as is customary in such cases in Russia. Treason acquittals are rare there.

The court in the Urals city of Yekaterinburg published a short video of Karelina sitting in a glass cage, wearing jeans and a green plaid shirt. She smiled faintly as reporters snapped photographs.

At least a dozen Americans are currently jailed in Russia, part of a growing list of foreign nationals who have found themselves caught up in the crisis of relations between Moscow and Washington during the Ukraine war.

Russia's Federal Security Service (FSB) detained Karelina in January while she was visiting her parents and young sister in Yekaterinburg.

Her former mother-in-law, Eleonora Srebroski, told Reuters in February that Karelina had travelled home around the New Year after her boyfriend surprised her with a plane ticket.

She had assured her boyfriend that Russia was "safe" and that he had no reason to fear her traveling there, according to Srebroski.

Initially arrested under a minor "petty hooliganism" statute, Karelina was later charged with treason.

Srebroski said Karelina had made a small donation to Razom for Ukraine, a New York-based nonprofit that sends non-military assistance to the country, invaded by Russian forces in 2022.

Karelina, who is in her early thirties, arrived in the U.S. in 2012 via a work-study program and was briefly married to Srebroski's son. Her ex-husband has described her as a fun-loving woman who didn't care much for politics.

Karelina's social media profiles feature photos of herself and friends on the beach and on trips, but without political messaging.

One photo from November 2021 shows her in a long dress, smiling and waving a small American flag, with the caption, "Citizenship".