The authors structured the different methodological approaches of the researchers to the nature of the concept "sect". Certain features of the sect as the authoritarian hierarchical organization producing manipulation of adherents´ consciousness are presented. It is proved that the extremist (terrorist) organizations and religious sects have a number of similar characteristics: the presence of ideological basis, a strict hierarchy and the corresponding functional, and therefore, there may be the cases of deformation from one to another. The attention on the problem of "hidden" (latent) sects in the regions is paid. The authors´ idea of the prevention of religious extremism and sectarianism, as part of regional policy, is suggested.