Iran warned Russia about the threat of a potential terror attack in its territory before the horrific massacre at a music venue near Moscow last month, according to a report. A source told Reuters that Tehran had shared information “about a possible big terrorist attack” with Moscow that had been “acquired during interrogations of those arrested in connection with deadly bombings in Iran.” Iranian intelligence said in January that it had detained dozens of people allegedly associated with twin bombings that killed nearly 100 people in Iran earlier in the month. It later announced that it had arrested a commander of the Afghanistan-based ISIS-Khorasan (ISIS-K)—the group which U.S. intelligence sources would subsequently blame for the Crocus City Hall attack in Moscow, where at least 144 people were killed on March 22. Another source told Reuters that the information given to Moscow did not contain specific information about when or where an attack could take place.