Russian officials say security forces have exchanged fire with suspected militants in the North Caucasus republic of Dagestan, killing three of the militants.

Authorities say the shootout began before dawn Sunday when Russian police surrounded a house where they say four militants had been hiding in the town of Dagestanskiye Ogni.

Officials say the security forces killed two men and a woman inside the house and wounded a second woman, who surrendered. One of the men was identified as a leader of an insurgent group in the city of Derbent. Explosive belts also were found at the scene.

Russian Interior Minister Rashid Nurgaliyev says the two women were trained as suicide bombers. He praised the operation against the militants, saying it had foiled a major terrorist attack.

Separatists in Russia's Caucasus republics have been fighting the Russian government for years. Predominantly-Muslim Dagestan is among the hardest-hit by the violence.