Two gunmen were killed in a special operation in the Dagestani city of Derbent. According to preliminary reports, three gunmen involved in terrorism-related crimes were blocked at a private house in Mamiashvili Street on Sunday, a spokesman for the Federal Security Service department in Dagestan told Itar-Tass. The gunmen opened fire in retaliation to demands to surrender, after that commandoes launched a storming of the house. The anti-terrorist operation regime was announced in Mamiashvili Street. "There are some suspicions that some more armed gunmen entrenched in the house, therefore an active stage of the operation was postponed until Monday morning," the spokesman said. Neither killed nor wounded law enforcers were reported.