Gunmen killed a Russian imam on his way to morning prayers in a restive southern region Saturday, a day after he spoke out against Islamic extremists, police said. Nurmagomed Gadzhimagomedov was shot by attackers in a car while walking from his home to his mosque in the Dagestani settlement of Gudben, they said.Gadzhimagomedov was a vocal critic of Islamic extremism who had spoken out against militants during a service at the mosque Friday, police said. They said the killing was "clearly a revenge attack" by Islamic militants. In July, a deputy chief mufti at the central mosque in the provincial capital, Makhachkala, was killed, along with his driver, by a roadside bomb blast.