FSB Arrests Minor After US Embassy Warns of Mass-Casualty Threat at Moscow Museum

Russia's Federal Security Service said Sunday it had detained a minor in connection with an alleged terrorist threat against a popular Moscow museum complex, a day after the U.S. Embassy in Moscow warned of a "credible threat of a mass casualty event" at the site.

The embassy's security alert, issued Saturday, urged people to avoid the Tsaritsyno Museum Reserve, stay alert and avoid crowds, and said Washington was coordinating a response with Russian authorities. The FSB confirmed receiving the American warning.

In a statement carried by Russian state media, the FSB said it had received the information from the United States through established channels and detained a minor Russian citizen after verifying it. According to the FSB, the suspect had posted photographs of himself on TikTok wearing tactical clothing and holding an object resembling an automatic weapon, along with photos taken at the museum reserve captioned "I found a place." A search of his devices uncovered a subscription to a neo-Nazi Telegram channel and numerous searches about past terrorist attacks and mass shootings, the FSB said. The claims could not be independently verified.

The grounds of the Tsaritsyno museum and park were closed "for technical reasons" and visitors were evacuated on Saturday evening; the site reopened as usual on Sunday, Russian media reported. The German Embassy in Moscow also reportedly issued a warning about a possible threat at the reserve.

The alert echoed a similar U.S. Embassy warning in March 2024, issued days before gunmen attacked the Crocus City Hall concert venue near Moscow in an attack that killed more than 150 people.

(Featured image: the U.S. Embassy in Moscow in March 2025. File photo. Photo: Sergey A. Demidov, CC BY 4.0.)