The U.S. Embassy in Russia issued a warning on the 7th that it had detected that "extremists" were plotting to launch an attack in Moscow in the next few days.
A source in the Russian intelligence service confirmed that the United States provided Russia with early warning of terrorist attacks. There is currently no official news confirming that the "Islamic State" was responsible for the shooting incident in Moscow, and the relevant information from the US media has not been verified. The death toll has now risen to 115.