By Jim Muir BBC Tehran correspondent

A senior religious figure in Iran has resigned and issued a bitter condemnation of the way the country is being run.

Ayatollah Jalaluddin Taheri has held the position of Friday prayers speaker in the major city of Isfahan for the past 30 years, but he has increasingly been at odds with Iran's hard-liners.

Taheri 'cannot tolerate the chaos'

Ayatollah Taheri's resignation came as a bombshell in the clerical establishment that has controlled much of the power in Iran since the Islamic revolution in which he himself played a significant role.

In his resignation statement, he delivered a blistering indictment of the country's rulers. It was ignored by the official media, but the full text was printed in reformist newspapers.

Ayatollah Taheri said he could not close his eyes to "tangible realities, and witness the stifling pain and unbearable suffering of people who were seeing the flowers of virtue being trampled, values collapsing, and spirituality being destroyed."

"When I remember the promises and pledges of the beginning of the revolution, I tremble like a willow thinking of my faith," he said.

All this threatens the existence of our country and our people

Ayatollah Taheri

He went on with a bitter litany of accusations against a system which he portrayed as deeply corrupt, self-serving, hypocritical and repressive.

In a clear reference to the hard-line vigilantes who have sometimes interrupted his sermons in Isfahan, the ayatollah spoke of "louts and fascists, who are a mixture of ignorance and madness, but whose umbilical cord is connected to the centre of power, and who are completely uncontrolled and beyond the law".

He also denounced the continued house arrest of Ayatollah Hossein-Ali Montazeri, a leading cleric who was once designated successor to Ayatollah Khomeini, but was later disgraced.

A resignation such as Ayatollah Taheri's, in such a manner, from a post conferred on him by Ayatollah Khomeini himself, is unprecedented in the 23 years of the Islamic republic.

Much of what Ayatollah Taheri had to say reflected a concern, which appears to be gaining ground within the clergy, that the growing rift between the powers that be and the people may be threatening to discredit the clergy as a whole.

While Ayatollah Taheri is associated with the reformist camp, a number of senior conservative clerics have also warned in recent months that the country risked a social explosion because of the system's failure to meet the expectations of the people.

In a first reaction to the ayatollah's resignation, Isfahan's five reformist members of parliament issued a statement sympathising with his pain and expressing their support.

Although reformists dominate parliament and also hold the presidency, they have been unable to implement the platform that won them landslide electoral victories because hard-line conservatives continue to control instruments to block reform and suppress dissent.