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 vested in a learned religious scholar referred to commonly as the Supreme Leader who, according to the constitution, is accountable only to the Assembly of Experts. US-Iranian 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 and 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 and UN economic sanctions and export controls because of its continued involvement in terrorism and conventional weapons proliferation. Following the election of reformer Hojjat ol-Eslam Mohammad KHATAMI as president in 1997 and similarly a reformer Majles (parliament) in 2000, a campaign to foster political reform in response to popular dissatisfaction was initiated. The movement floundered as conservative politicians, through the control of unelected institutions, prevented reform measures from being enacted and increased repressive measures. Starting with nationwide municipal elections in 2003 and continuing through Majles elections in 2004, conservatives reestablished control over Iran's elected government institutions, which culminated with the August 2005 inauguration of hardliner Mahmud AHMADI-NEJAD as president. In December 2006 and March 2007, the international community passed resolutions 1737 and 1747 respectively after Iran failed to comply with UN demands to halt the enrichment of uranium or to agree to full IAEA oversight of its nuclear program. In October 2007, Iranian entities were also subject to US sanctions under EO 13382 designations for proliferation activities and EO 13224 designations for providing material support to the Taliban and other terrorist organizations.