Shortwave broadcasting in the United States is unique in that the United States allows private ownership of commercial and non-commercial shortwave stations that are not relays of existing AM/MW or FM radio stations, as are common in Africa, Europe, Asia, Oceania and Latin America. In addition to private broadcasters, the United States also has government broadcasters and relay stations for international public broadcasters. Most privately owned shortwave stations have been religious broadcasters, either wholly owned and programmed by Roman Catholic and evangelical Protestant charities or offering brokered programming consisting primarily of religious broadcasters. To better reach other continents of the world, several stations are located in far-flung US territories. Shortwave stations in the USA are not permitted to operate exclusively for a domestic audience; they are subject to antenna and power requirements to reach an international audience.