LOS ANGELES (NewsNation) — The boyfriend of a dual Russian American citizen who is being detained overseas on suspicion of treason said she’s the “kindest person” you could ever meet.

Russia‘s FSB said Tuesday it had detained a woman, since identified as 33-year-old Ksenia Karelina, in the Urals mountain city of Yekaterinburg on suspicion of treason, according to a report by state news agency TASS.

TASS reported the Los Angeles resident had been placed in pretrial detention after donating money to the Ukrainian military.

“My girlfriend, Ksenia, has been detained in Russia,” boyfriend Chris van Heerden said on Instagram. “She’s in pretrial confinement. She’s an American citizen and a Russian citizen. If you know Ksenia, you know she’s the sweetest, kindest person you will ever meet. Full of love, joy. She’s a lovely person.”

The FSB, the main successor agency to the Soviet-era KGB, said in its statement that it had “suppressed the illegal activities of a 33-year-old resident of Los Angeles, who has dual citizenship of Russia and the United States of America, involved in providing financial assistance to a foreign state in activities directed against the security of our country.

“Since February 2022, she has been proactively collecting funds in the interests of one of the Ukrainian organisations, which were subsequently used to purchase tactical medicine items, equipment, weapons and ammunition by the Armed Forces of Ukraine.”

A spokesperson for the U.S. Embassy in Moscow said: “We are aware of the reports; however, due to privacy considerations, we have nothing further to convey at this moment.”

Reuters contributed to this story.