The warning triggered a security operation at the historic estate, with Russian authorities temporarily closing the complex and evacuating visitors and staff Russia's Federal Security Service (FSB) has detained a minor suspected of planning a terrorist attack at a popular museum and park complex in Moscow, following a tip-off from the United States about an imminent mass-casualty threat.The FSB said on Sunday that it had received information from US counterparts through established partner channels about preparations for an attack at the Tsaritsyno Museum Reserve in southern Moscow. The security agency said the information had prompted it to take appropriate measures...