Eleven people have been detained after an attack at a Moscow concert hall that killed 60, the head of Russia’s Federal Security Service told President Vladimir Putin on Saturday, according to Russian state news agency Tass. Another 145 people were injured in the attack by assailants who burst into a concert hall and sprayed the crowd with gunfire. The Islamic State group claimed responsibility for the attack in a statement posted on affiliated channels on social media. The attack was the deadliest in Russia in years and left the concert hall in flames and with a collapsing roof.