Iranian supreme leader Ayatollah Ali Khamenei called on Saturday for more transparency in elections due in May following allegations of electoral fraud in the last polls.
He also warned against any foreign funding and interference.
State media carried election guidelines issued by Khamenei, who has the final say on all matters of state. They called for "setting the scope and type of expenses and sources of legal and illicit campaign expenses by candidate and increasing the transparency of resources..."
Election fraud is rarely reported openly, but the head of the Guardian Council, the top election watchdog, said after parliamentary elections in early 2016 that "vote-buying is becoming more common" and should be fought.
Iran will hold its next presidential election in May 2017, a vote in which pragmatist President Hassan Rohani may seek a second term to push ahead with reforms resisted by powerful hardliners.
"The use of foreign resources, both financial and promotional support by candidates and parties is banned," said one of the 18 articles of Ayatollah Khamenei's guidelines, issued after consultation with a top clerical body, according to state media.
Khamenei has often called for vigilance against what he calls a "soft war" mounted by the West and aimed at weakening the clerical establishment.
Hardline allies of Khamenei, worried about losing their grip on power, have accused President Rohani of betraying the anti-Western values of the 1979 Islamic revolution that toppled the U.S.-backed shah.
Former president Mahmoud Ahmadinejad said last month he would not run in the presidential elections, bowing to the wishes of Ayatollah Khamenei who warned his candidacy would increase divisions in Iran.
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