The Islamic State, also known as ISIS, has claimed responsibility for a deadly attack on a concert hall in Moscow, Russia. The attack resulted in at least 40 deaths and over 100 injuries. Armed individuals stormed the venue, opening fire and detonating explosives among the crowd. This marks a significant escalation in ISIS's external attacks, as the group has been relatively quiet in recent times. The United States had reportedly warned Russian officials about the possibility of such an attack, indicating that ISIS-K, the branch based in Afghanistan, was planning an assault on Moscow.