Russia’s main security agency said on Tuesday that it had arrested a dual citizen of Russia and the United States on accusations of committing state treason by raising funds for Ukraine.
The Federal Security Service, known as the F.S.B., identified the detainee as a 33-year-old woman who lives in Los Angeles. It said in a statement that she had raised money for a Ukrainian organization that bought weapons and other equipment for Ukraine’s military.
Perviy Otdel, a group of Russian lawyers who specialize in cases involving accusations of treason and other politically charged allegations, said that the woman had been accused of treason for sending just over $50 to Razom for Ukraine, a New York-based nonprofit organization that sends assistance to the country.
The F.S.B. said that she had been arrested in the city of Yekaterinburg, in central Russia. RIA Novosti, a Russian state news agency, published a video that it said showed the woman, wearing a white hat that covered her eyes, being handcuffed and escorted by masked security service officers.
If convicted, she could face up to 20 years in prison.
The detention of American citizens on Russian soil in recent years has raised suspicions that the Kremlin views them as valuable assets to be traded for high-profile Russians held in custody in the United States and other Western countries.
On the same day that the woman’s arrest was announced, a Moscow court rejected an appeal by Evan Gershkovich, an American reporter for The Wall Street Journal whom Russia arrested last spring on an espionage charge, to lift his pretrial detention. It ruled that Mr. Gershkovich — who, along with his employer and the American government, has denied the charge against him — must stay in prison at least until the end of March.
A State Department spokesman, Matthew Miller, told reporters on Tuesday that the United States had requested consular assistance for the woman, but “that has not yet been granted.” He said that Russia in effect “does not recognize” dual citizenship and considers such people “to be Russian citizens first and foremost.”
A Russian news outlet, Media Zona, identified the detainee as Ksenia Karelina. Perviy Otdel, the legal group, identified her as Ksenia (Karelina) Khavana, with Karelina most likely being her maiden name. Perviy Otdel said she was arrested at the end of January and accused of treason on Feb. 7.
According to Ms. Karelina’s profile on VK, a Russian social network, she received U.S. citizenship in 2021. Her profile, which identified her as a student at the University of Maryland in Baltimore, said that she had graduated from Urals Federal University in Yekaterinburg in 2014.
In an interview at her home in Maryland on Tuesday, Ms. Karelina’s former mother-in-law, Eleanora Srebroski, said that Ms. Karelina was once married to her son, Evgeny. She grew up in Yekaterinburg and came to the United States for a work-study program, working that summer at a fruit stand in Randallstown, Md., selling fruits and vegetables. (Ms. Srebroski, 56, is herself from Russia, and grew up about 120 miles away from Yekaterinburg, she said.)
The couple married in 2013, but after they split up about two years later, Ms. Karelina left Maryland for Los Angeles, where she worked at a Beverly Hills hotel as an aesthetician and spa manager, Ms. Srebroski said.
Isabella Koretz, the president of Ciel Spa in Beverly Hills, Calif., confirmed that Ksenia Khavana has worked there for eight years. A statement put out by the spa said that she had traveled to Russia to visit her 90-year-old grandmother, parents and a younger sister, and that she was now being held in a Russian prison, wrongly accused of treason “for allegedly donating $51.80 to a Ukrainian charity in the U.S.”
“To know Ksenia is to love her,” the statement said. “This heartbreaking news is so difficult to share, but it must be done to spread her story and seek justice.”
Mrs. Srebroski said that she had learned of the arrest of her former daughter-in-law only that day, when a reporter called.
“She’s a beautiful, beautiful person,” said Mrs. Srebroski. “She just brings light everywhere she goes.”
She said she would not be surprised if her former daughter-in-law had donated money for Ukraine: “Anyone who is hurt, she is on their side.”
Mykola Murskyj, the director of advocacy for Razom for Ukraine, said he could not comment on the nonprofit’s donor base or any contributions, but he said the group was alarmed by the arrest.
He said that Razom for Ukraine, which is focused on humanitarian aid relief work, provides tactical, medical first-aid kits and other supplies to the country’s front lines. He disputed the F.S.B.’s claim that the group had provided weapons to the military.
“That’s nonsense,” Mr. Murskyj said. “We do provide first-aid supplies to Ukrainian soldiers and those fighting for Ukraine’s independence, but never weapons or ammunition.”
Mr. Miller, the State Department spokesman, declined to speculate on whether the United States might formally determine the woman to be “wrongfully detained,” as it has for two Americans already in custody in Russia, Mr. Gershkovich and Paul Whelan. Such a determination would mean the United States considers a detainee to be the equivalent of a hostage, allowing for special efforts to win his or her release.
The number of state treason cases in Russia has been growing steadily since its full-scale invasion of Ukraine in early 2022. Last year, about 50 people were accused of the offense, according to Perviy Otdel, ranging from high-profile critics of the Kremlin to a student accused of photographing Russian Army formations in his town.
A court in Yekaterinburg was scheduled to hear an appeal by the woman whose arrest was announced on Tuesday, according to the court’s website, which also said that she was accused of treason.
Michael Crowley Kitty Bennett, JoAnna Daemmrich, Rachel Parsons and Amanda E. Newman contributed reporting.