Russia arrests minor after US Embassy warns of ‘credible threat of a mass casualty event’ in Moscow

Russia's Federal Security Service (FSB) said Sunday it had detained a minor after the US Embassy in Moscow warned of a "credible threat of a mass casualty event" at the Tsaritsyno Museum-Reserve in the Russian capital.

Authorities canceled planned cultural events at the museum-reserve and strengthened security measures in the surrounding area, the FSB said.

"As a result of these operations, a Russian minor was detained," the FSB said in a statement.

It said the individual had posted videos on TikTok showing himself wearing tactical gear, including a balaclava, cap, goggles and headset, while holding an object resembling an automatic weapon. He also posted photos taken at the museum-reserve with the caption: "I found a place."

A search of the minor's residence uncovered the clothing and accessories, the FSB said.

"Furthermore, an examination of his communication devices revealed a TikTok account used to post threats, a subscription to a neo-Nazi channel on the messaging app Telegram, and a significant number of search queries regarding past terrorist attacks, mass killings, and other acts of violence," it said.

The FSB thanked the US for providing the information.

The US Embassy in Moscow on Saturday warned of "a credible threat of a mass casualty event" at a palace museum and park reserve in the Russian capital, urging people to avoid the area, remain alert and avoid crowds.

It said the US government was coordinating with Russian authorities in response to the threat.