Russia’s Federal Security Service (FSB) said on Saturday, 31 October 2026, that it had received information from the United States through partner channels about preparations for a terrorist attack in Moscow and was taking appropriate measures, Agerpres reports citing RIA, Reuters and AFP.

The US Embassy in Moscow said separately it was “aware of a credible threat of a mass casualty event” today, 31 October, at the Tsaritsyno Museum Reserve, and that the US government was coordinating with Russian authorities. Americans were advised to avoid the site, stay alert, keep phones charged and carry ID.

RIA, citing law enforcement, said the Tsaritsyno museum-reserve was temporarily closed and park access restricted. Some local outlets carried conflicting notes — a museum representative told channels staff had no threat information — but the diplomatic alert and FSB confirmation remain the day’s official thread.

The southern Moscow complex, with neo-Gothic palaces and a large park, is a popular destination; cultural events were listed for Saturday. The US Embassy issued a similar warning in March 2024, days before the Crocus City Hall attack that killed more than 140 people.

The FSB did not detail the attack type or alleged perpetrators. Pending further statements, the picture is a bilateral warning, security measures at Tsaritsyno and advice for foreign publics to steer clear of the area.

Image: Tsaritsyno Grand Palace, Moscow (Wikimedia Commons, CC BY-SA 3.0).

Sources consulted: FSB: US warned Russia of a planned attack in Moscow - AGERPRES.