ARUSHA, Tanzania (Reuters) - A Rwandan who led an extremist militia group during the country`s 1994 genocide was sentenced by a United Nations court on Friday to 15 years in prison. Omar Serushago, a local leader of the Interahamwe, had pleaded guilty to genocide and crimes against humanity. He is the first genocide convict at the International Criminal Tribunal for Rwanda (ICTR) to receive less than the maximum life sentence. Presiding Judge Laity Kama said Serushago, 37, deserved a degree of clemency because he surrendered voluntarily, had since cooperated with the court and expressed remorse for his crimes. "It is important to recall that the accused pleaded guilty to four counts namely genocide and three counts of crimes against humanity," Kama told the court. Serushago, wearing a colourful African shirt, smiled slightly at his lawyer Mohamed Ismail after sentence was passed. The tribunal has now sentenced

three genocide convicts, including Rwanda`s prime minister at the time of the 1994 massacres of an estimated 800,000 Tutsis and Hutu moderates. The other two received life sentences.