Crocus City Hall (Photo: resources of propagandists of the Russian Federation)

Iran warned Russia of a possible major "terrorist operation" on its territory ahead of the mass shooting at the Crocus City Hall concert venue in Moscow, Reuters reported, citing three unnamed sources familiar with the matter.

"A few days before the attack in Russia, Tehran shared information with Moscow about a possible major terrorist attack inside Russia that had been obtained during interrogations of individuals arrested in connection with deadly explosions in Iran," one of the sources said.

A second source, who also wished to remain anonymous due to the matter's sensitivity, said that the information Iran provided to Moscow about the impending attack did not include specific details about the timing or exact target.

A third source said, "As Iran has been a victim of terrorist attacks for years, the Iranian authorities fulfilled their obligation to warn Moscow based on information obtained from arrested terrorists."

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