Iran, once known as Persia, is a major regional power. Its size, history, and resources have enabled it to exert significant influence over its neighbors in the Middle East and Central Asia. Iran is one of the world's few countries where Shiite Muslims are a majority, and since 1979 it has been ruled by Muslim clerics as a theocracy. Many world leaders are concerned that Iran is trying to develop nuclear weapons, which would disrupt the fragile balance of power in the volatile Middle East. Since 2006, the United States, Russia, China, the United Kingdom, France, and Germany have imposed economic sanctions on Iran, and negotiated with Iranian leaders in hopes of convincing the state to give up its weapons program.