Russia's Federal Security Service (FSB) says a security operation in Kazan on October 24 prevented a major terrorist attack set to take place during an Islamic holiday.
The FSB said on October 25 it obtained information a militant group was preparing a "large-scale terrorist attack in crowded areas" on October 26.
The attack was timed to happen as Muslims in Russia's Tatarstan region mark the Kurban Bayrami holiday.
The FSB said three militants and one member of the special forces were killed in the special operation.
The FSB also said the militants were involved in attacks on state-sanctioned Muslim clergy last summer.
Based on reporting by ITAR-TASS, Interfax, and "Moskovsky komsomolets"