Religious antagonisms have often been the main source of occurrences threatening the national security of many countries. Since the islamization of the Balkan region to the present day there have, to a greater or lesser extent, been religious antagonisms between Serbian and Muslim population, and Serbian national interests have been threatened by the manifestation of Muslim extremism, as a consequence of centuries-long presence of the Ottoman Islamism. From the late 20th century the national security of the Republic of Serbia has been further endangered by the phenomenon arising from religious antagonisms between the followers of the Wahhabi movement, on the one hand, and Serbian and traditional Muslim population, on the other hand. They result from the manifestation of a new form of Islamism based on the fundamentalist ideology of Wahhabism. Unlike the former Ottoman Islamism, modern Islamism of a part of the Muslim population in the Republic of Serbia is characterized by significantly stronger fanaticism and radicalism, which has resulted in the use of extreme forms of violence, among which terrorism is nowadays the most common. Systematic use of this form of political violence has resulted in pronounced and constant threats to national security of the Republic of Serbia.