Society is on the threshold of an explosion. If popular discontent increases, society and the regime will be threatened

Ayatollah Ebrahim Amini

He told a meeting in Qom, south-west of the Capital Tehran, that ordinary Iranians were extremely unhappy with the current situation, and that officials should not disregard their views.

"If popular discontent increases, as is the case, society and the regime will be threatened," the ayatollah warned.

BBC Teheran correspondent Jim Muir says such dire warnings are common among reformists - including President Mohammed Khatami.

However Ayatollah Amini is a pillar of the conservative and religious establishment which still controls most of the powerful institutions of state.

'Disappointment' with revolution

The Ayatollah's statement - which was made on Wednesday - has made front page headlines in the reformist Tehran newspapers.

President Khatami has repeatedly warned of social unrest

Reformists, who control parliament and the presidency, have for a long time accused conservatives, such as Ayatollah Amini, of blocking all progress or change.

Ayatollah Amini said many promises had been made during the Islamic Revolution of 1979, and people had expected their lives to change.

The objective of the Islamic revolution, he said, was not to replace one government with another without altering the behaviour of the state.

The ayatollah said the Iranian revolution occurred "because the people were discontented with the injustice and discrimination of the imperial regime".

No regime "can maintain itself in power by force," he warned.

Khatami warning

Ayatollah Amini's warning follows a similar statement by reformist President Mohammad Khatami earlier this month.

"Our society is on the threshold of disorder," Mr Khatami said.

"Iran did not vote for me but voted for justice and freedom in the framework of the constitution."

The Iranian news agency has quoted close associates of Mr Khatami saying he has repeated his threat to resign in frustration at his inability to push through reforms.