By Sadeq Saba
BBC News regional analyst
Iran's clerical leaders have come under attack from one of the country's most influential conservative academics.
Iran's political institutions are dominated by clerics, at their head Ayatollah Ali Khamenei
Ali Mottahari, a Tehran University philosophy teacher, has accused the clerics of creating a schism between religion and the people.
Mr Mottahari's father was the late Ayatollah Morteza Mottahari, the intellectual leader of Iran's Islamic Revolution in 1979.
He told the Iranian news agency that clerics should stay out of government.
Ali Mottahari has impeccable Islamic and revolutionary credentials.
When he calls for a non-clerical government in Iran, he cannot easily be accused of favouring Western liberalism.
Mr Mottahari said when clerics entered the government, they became distanced from their spiritual duties.
He said his late father, Ayatollah Mortaeza Mottahari, who is regarded as one of the founders of the Islamic Republic, was against the idea that clerics should get involved in government.
Mr Mottahari said only under special circumstances should clerics be allowed to assume government posts. But he added that he believed that clerics, like other people, could become judges and members of parliament.
Mr Mottahari's comments suggest that secularism may be now gaining ground even among conservative Muslims.
For sometime, liberal Islamists in Iran have been calling for a separation of religion and state. But this is the first time that such a prominent conservative figure has echoed such calls.