Iran warned Russia of a security threat before the Moscow attack and arrests in Dagestan. One of the detained men admitted that he personally brought weapons to the attackers.
Gunmen opened fire with automatic weapons on concert-goers on March 22 inside Crocus City Hall. At least 144 people were killed in the deadliest attack on Russian soil in 20 years, for which the Islamic State claimed responsibility. The four men, whom Russia accuses of carrying out the attack, are ethnic Tajiks.. A diplomatic source in Tajikistan confirmed that Tehran. recently discussed with Dushanbe the issue of increasing the involvement of ethnic T.ajiks in armed activities.