A divine authority told me to tell the people to make a general repentance. Why? Because calamities threaten us," Sedighi said.
Referring to the violence that followed last June's disputed presidential election, he said, "The political earthquake that occurred was a reaction to some of the actions (that took place). And now, if a natural earthquake hits Tehran, no one will be able to confront such a calamity but God's power, only God's power. ... So let's not disappoint God."
The Iranian government and its security forces have been locked in a bloody battle with a large opposition movement that accuses Ahmadinejad of winning last year's vote by fraud.
Ahmadinejad made his quake prediction two weeks ago but said he could not give an exact date. He acknowledged that he could not order all of Tehran's 12 million people to evacuate. "But provisions have to be made. ... At least 5 million should leave Tehran so it is less crowded," the president said.
Minister of Welfare and Social Security Sadeq Mahsooli said prayers and pleas for forgiveness were the best "formulas to repel earthquakes."
"We cannot invent a system that prevents earthquakes, but God has created this system and that is to avoid sins, to pray, to seek forgiveness, pay alms and self-sacrifice," Mahsooli said.