Moscow was mourning on Tuesday after the metro bombings that killed 39 people on Monday. There was no immediate claim of responsibility fo the attacks, but the "Caucasus Emirate" group led by Chechen Islamist chief Doku Umarov had recently threatened to attack Moscow. Born out of the Chechen separatist movement, it has now grown into a full, radical islamist group, spread to the entire North Caucasus.Duration: 01:32
