Four gunmen were killed in a special operation on Makhachkala's northwestern outskirts on Saturday, Itar-Tass reported. The gunmen were members of the so-called Makhachkala armed band group and were involved in a series of attacks on law-enforcement officers, a source at the Federal Security Service's department in Dagestan said. Security service and police units blocked the gunmen in a private house in the settlement of Tarnair on Makhachkala's outskirts at about 05:00 Moscow time on Saturday morning. The blocked men refused to surrender and opened fire. They were killed in the retaliatory operation. Their identities have yet to be established. Sappers are working at the site. The gunmen had submachine guns, pistols and other firearms. A state of a counter-terrorist operation was imposed in the settlement from 06:00 Moscow item. Nobody was hurt among the security service and police personnel.