The FSB received data from the US about the preparation of a terrorist attack in Moscow in this regard, the secret service officers are carrying out the necessary work, the FSB added. The US Embassy in Moscow warned of a real threat of a mass incident with a large number of victims at the Tsaritsyno Museum Reserve in Moscow. The warning applies to Saturday, October 31. American citizens have been advised to avoid the area, remain vigilant and stay away from crowds Bloomberg.