A music concert in suburban Moscow turned into a horrific scene of a terrorist attack on March 22, as gunmen armed with automatic weapons and Molotov cocktails killed more than 130 people and left dozens injured.

In the aftermath of the attack, speculation arose regarding the perpetrators.

Despite Ukraine promptly denying any involvement, Russian President Vladimir Putin utilized a brief televised address to suggest, without substantiating evidence, that Ukraine may have been complicit in aiding the terrorists’ escape.

However, ISIS has claimed responsibility for the attack. Russia, however, has yet to officially acknowledge ISIS’s role. Nonetheless, irrespective of the group behind the attack, the events in Moscow highlight two significant concerns.