Russian officials have said 93 people were killed by assailants who burst into a concert hall in western Moscow and sprayed the crowd with gunfire. The head of Russia’s Federal Security Service told Russian President Vladimir Putin that four people directly involved in the attack on the Crocus City Hall on Moscow’s western edge were among 11 detained in the aftermath, Russian state news agency Tass said. The so-called Islamic State group (IS) claimed responsibility for the attack in a statement posted on affiliated channels on social media.