(Xinhua) -- The gunmen killed in the Dagestan Republic of Russia may have been plotting a series of terrorist attacks, Dagestani Interior Minister Adilgerei Magomedtagirov said on Saturday. Three gunmen were killed in a special operation in Dagestan's Kizlyar district on Saturday. The bodies of two of them have been found. "These militants were members of Takhir Badayev's group involved in up to 50 terrorism-related crimes committed in the Shelkovskoy district of the Chechen republic," Magomedtagirov was quoted by the Interfax news agency as saying in the capital city of Makhachkala. A cache containing 18 explosive devices has been found at the scene, according to Nikolai Gryaznov, director of the Federal Security Service's (FSB) branch for Dagestan and commander of the Saturday operation. The militants apparently plotted a series of terrorist attacks intended to destabilize the republic, he said. "The killed have not been identified yet. But their actions during the gun battle suggest that they were well-trained professionals," Gryaznov said. Police are picking through the rubble for the body of the third militant, he said.