|The Iranian political system balances Islamic theocracy with elements of modern democracy [EPA]
After the 1979 Islamic Revolution, Iranians approved in a referendum a new constitution for a hybrid political system which combines elements of democracy with unelected religious leadership.
The Iranian political system is therefore a mix of appointed and directly elected institutions.
In recent years, Iran's conservative body of appointed institutions have faced a challenge from reformist politicians directly elected by the people, yet the supreme leader remains the overarching authority over the country.
The supreme leader is the highest ranking political and religious authority in the country.
He appoints the chiefs of posts such as the commanders of the armed forces, chief judges, prosecutors as well as six of the Islamic jurists who sit on the 12-member Guardian Council.
|Khamenei is Iran's second supreme leader since the 1979 Islamic Revolution [AFP]
Ayatollah Ali Khamenei has held the position of supreme leader since 1989, when he was selected by the Assembly of Experts.
The Assembly of Experts is an 86-member chamber that monitors the highest religious leader's performance.
Ayatollah Ruhollah Khomeini, Khamenei's predecessor, was the figurehead of the 1979 Islamic Revolution that saw the overthrow of the Shah.
The elected president is subordinate to the appointed supreme leader and oversees economic policy and the management of national affairs.
The president can sign agreements with foreign governments and approve ambassadorial appointments and, as such, is responsible for the functions of the executive.
He selects the Council of Ministers - the cabinet - although his choices must be approved by parliament.
|Ahmadinejad has divided public opinion in Iran since coming to power in 2005 [AFP]
He also chairs the Supreme National Security Council, which co-ordinates defence and security policy, although the supreme leader still has the final say on the running of the armed forces, defence and nuclear and foreign policy.
Presidential terms in Iran are set at four years. A sitting president can hold no more than two consecutive terms in office.
Mahmoud Ahmadinejad, the current president, has pursued a conservative agenda, and has been criticised by reformist presidential candidates in the June 2009 election.
The Guardian Council is an unelected body of 12 clerics and Islamic jurists. Half of those serving on the council are appointed directly by the supreme leader, the others are approved by the Iranian parliament.
The council has the constitutional authority to veto parliamentary decisions and vet electoral candidates. Over 400 people who were looking to contest this year's presidential election were rejected by the council, including all the female potential candidates.
At present, the council is under the control of religious conservatives.
Parliament - known as the Majlis - is the national legislative body, with 290 publicly elected representatives.
Elections for the parliament are held every four years in a popular vote, although all potential candidates for the legislature must first be approved by the Guardian Council.
The legislature can summon or impeach ministers or the president, and also drafts legislation and approves the national budget.
Reformists dominated parliament in 2001, but conservative politicians clawed back their majority in elections held four years later.
The flagship force of the Iranian military is the Revolutionary Guard, although it is run in conjunction with the standard armed forces.
The Revolutionary Guard was set up in the wake of the Islamic Revolution to protect the new political leaders and bodies and uphold the spirit of the revolution.
The supreme leader selects the commanders of both the Revolutionary Guard and the regular forces.
Any differences between the parliament and the Guardian Council are adjudicated by the Expediency Council, a body which advises the supreme leader.
The council is made up of prominent members of Iranian society, such as religious leaders and politicians. Members of the council are appointed by the supreme leader.
For the last four years the council has possessed special powers over branches of government, as instructed by the supreme leader.