FACTBOX: Issues in Iran's presidential election race

(Reuters) - Iranians vote on Friday in a presidential election that will test the popularity of President Mahmoud Ahmadinejad against rivals who criticize his combative stance on the nuclear issue and his handling of the economy.

Following are some of the campaign issues and positions of the four candidates cleared to run by the Guardian Council:

NUCLEAR

The candidates have promised no major change in Iran's nuclear policy, saying such matters of state are decided by Supreme Leader Ayatollah Ali Khamenei, but they have signaled subtle differences in approach. Moderates, such as former Prime Minister Mirhossein Mousavi and former Parliament Speaker Mehdi Karoubi, have faulted Ahmadinejad for isolating Iran by denying the Holocaust and making fiery anti-Western speeches. However, no candidate has suggested that Iran could address the West's concerns over its nuclear program and halt sensitive work.

RELATIONS WITH THE UNITED STATES

As in the 2005 presidential election, all candidates have said they are open to the idea of resuming relations with the United States. This reflects how popular such a move would be among Iranians weary of a rift that has lasted almost three decades. But nearly all the candidates demand "fundamental" changes in U.S. policy toward Iran. These could include removing the Islamic Republic from the U.S. list of terrorism sponsors or unfreezing billions of dollars in Iranian assets seized in the United States after the 1979 Islamic revolution.

ECONOMY

Candidates have offered few detailed ideas on how to improve the economy in Iran, which has the world's second biggest oil and gas reserves. Critics say the government did not save enough when oil prices were high to maintain spending after they fell below $40 a barrel in February from a July peak of $147. Prices have since firmed to around $70 a barrel. Many Iranians complain of inflation, which hit almost 30 percent last year but which has since dipped, and rising unemployment.

Karoubi has said he will distribute shares of oil income to all Iranians aged over 18. He advocates greater privatization.

Mousavi, who administered a relatively efficient state rationing system when he was prime minister during the 1980-88 Iran-Iraq war, now favors more liberalization of the economy.

Ahmadinejad's spending policies have been criticized as inflationary and wasteful of windfall oil revenue earned by the world's fifth biggest crude exporter. He has promised to alleviate poverty and reduce dependence on oil income, which accounts for 80 percent of hard currency earnings. His power base rests on poorer segments of Iran's 70 million people.

HUMAN RIGHTS

All candidates have promised to uphold freedom of speech and improve women's participation in government and decision-making in Iran, often criticized abroad for its human rights record. Karoubi and Mousavi have opposed Ahmadinejad's drive to enforce what hardliners define as Islamic dress and social behavior.

(Writing by Parisa Hafezi; Editing by Alistair Lyon)