MOSCOW (AP) — President Vladimir Putin says authorities have detained 11 people after gunmen stormed a concert hall in Moscow in a grisly attack that left at least 133 people dead. Russia’s Investigative Committee said four of those detained were directly involved in Friday’s attack that left left the sprawling shopping mall and music venue smoldering with a collapsed roof. Russian President Vladimir Putin suggested Saturday that Ukraine was linked to the attack, even though the Islamic State group claimed responsibility. Ukraine has strongly denied any involvement and accused Moscow of using the attack to try to stoke fervor in its war effort. A U.S. intelligence official told The Associated Press that U.S. agencies had confirmed that that IS’s Afghanistan affiliate was responsible.