 Iran warned Russia of terror threat before Crocus City Hall attack. Iran warned Russia about the possibility of a major terrorist operation on its territory ahead of the mass killing at the suburban Crocus City Hall. Reuters reported this, citing sources. Days before the attack in Russia, Tehran shared information with Moscow about a possible big terrorist attack inside Russia that was acquired during interrogations of those arrested in connection with deadly bombings in Iran, a source said. In January, the Iranian Ministry of Intelligence announced the arrest of 35 suspects, linked to the explosions in the southeastern city of Khurman on the 3rd of January, which resulted in the death of approximately 100 people. On the 19th of January, the Ministry stated that it had arrested a commander of Islamic State's Afghanistan-based branch, ISIS Korasan. A second source, which also preferred to remain anonymous due to the sensitivity of the issue, reported that the information provided by Tehran to Moscow about the impending attack lacked details regarding the time and exact target. The members of ISIS Korasan were instructed to prepare for a significant operation in Russia. One of the terrorists said some members of the group had already travelled to Russia, the second source said. As Iran has been a victim of terror attacks for years, Iranian authorities fulfilled their obligation to alert Moscow based on information acquired from those arrested terrorists. A third source, a high-ranking security service official said, according to Reuters, the source, familiar with US intelligence about the upcoming attack in Russia, reported that they were based on intercepted conversations between ISIS Korasan militants. Reuters notes that the Iranian Ministry of Foreign Affairs and the Kremlin did not respond to requests for comment on this story. The White House also did not provide any comments. The White House. The White House. The White House.