Known as Persia until 1935, Iran became an Islamic republic in 1979 after the ruling monarchy was overthrown and the shah was forced into exile. Conservative clerical forces established a theocratic system of government with ultimate political authority nominally vested in a learned religious scholar. Iranian-US relations have been strained since a group of Iranian students seized the US Embassy in Tehran on 4 November 1979 and held it until 20 January 1981. During 1980-88, Iran fought a bloody, indecisive war with Iraq that eventually expanded into the Persian Gulf and led to clashes between US Navy and Iranian military forces between 1987-1988. Iran has been designated a state sponsor of terrorism for its activities in Lebanon and elsewhere in the world and remains subject to US economic sanctions and export controls because of its continued involvement. Following the elections of a reformist president and Majlis in the late 1990s, attempts to foster political reform in response to popular dissatisfaction floundered as conservative politicians prevented reform measures from being enacted, increased repressive measures, and made electoral gains against reformers. Parliamentary elections in 2004 and the August 2005 inauguration of a conservative stalwart as president, completed the reconsolidation of conservative power in Iran's government.