A Russian court on Thursday sentenced U.S.-Russian dual national Ksenia Khavana to 12 years in prison on a treason conviction for allegedly raising money for the Ukrainian military.

Khavana, whom Russian authorities identify by her maiden name of Karelina, was arrested in Yekaterinburg in February. She pleaded guilty in her closed trial last week, news reports said.

Khavana reportedly obtained U.S. citizenship after marrying an American and moving to Los Angeles. She had returned to Russia to visit her family.

Russia's Federal Security Service said she "proactively collected money in the interests of one of the Ukrainian organizations, which was subsequently used to purchase tactical medical supplies, equipment, weapons, and ammunition for the Ukrainian armed forces."

The rights group The First Department said the charges stem from a $51 donation to a U.S. charity that helps Ukraine.

Since sending troops into Ukraine in February 2022, Russia has sharply cracked down on dissent and has passed laws that criminalize criticism of the operation in Ukraine and remarks considered to discredit the Russian military. Concern has risen since then that Russia could be targeting U.S. nationals for arrest.

In the largest Russia-West prisoner exchange since the end of the Cold War, Russia this month released Wall Street Journal reporter Evan Gershkovich and American corporate security executive Paul Whelan, both of whom were imprisoned on espionage convictions, and U.S.-Russian dual national Alsu Kurmasheva, a Radio Liberty/Radio Free Europe journalist sentenced to 6 1/2 years for spreading "false information" about the Russian military.

Russia also released several prominent opposition figures who were imprisoned for criticizing the Ukraine military operation.