TEHRAN, Jan 11: Iran was plunged into a major political crisis on Sunday after powerful conservatives moved to disqualify massive numbers of reformists from standing in next month's crucial parliamentary elections , a move one MP branded a "coup d'etat".

There was uproar in parliament, held for the past four years by moderates loyal to President Mohammad Khatami, as it emerged that the Guardians' Council had also barred leading pillars of the reform movement, including a brother of the president.

"I consider this rejection of candidates to be an illegal coup d'etat and an act of regime change by non-military means," fumed Mohsen Mirdamadi, head of the parliament's foreign policy and national security commission.

Mirdamadi was one of over 80 incumbent reformist MPs who have been barred from standing in the February 20 election by the 12-member Guardians' Council, an unelected political oversight body and bastion of the religious right.

He said the bulk of disqualified MPs were found to have been in violation of an article in the electoral law that stipulates candidates must show their commitment to Islam and respect the position of Ayatollah Ali Khamenei as supreme leader.

Mohammad Reza Khatami, the president's brother and head of the Islamic Iran Participation Front (IIPF) - the Islamic republic's largest pro-reform party - said the move was a mockery of democracy.

"If the situation continues, the conditions for voting will not exist, people will not be prepared to vote and naturally we are heading in the direction of a national election boycott," he said.

"We demand the president and the government... not be responsible for organizing undemocratic elections," he said, while warning of dire consequences for Iran's international image.

The Majlis building, where reformist MPs gathered for an all-night sit-in, would be transformed into "a centre of resistance against this illegal action," he said.

As one senior politician revealed a group of up to eight cabinet ministers had "prepared their letters of resignation", the president himself issued an impassioned appeal for calm.

"Violence must be averted. Inshallah (God willing), with calm we can solve this problem. We should not do anything to stoke tensions," Khatami said, alluding to fears the latest explosion of reformist-conservative tensions could again bring out pro-reform students - already frustrated with the slow pace of reforms - onto the streets.

And speaking during a stormy Majlis session carried live on state radio, parliament speaker Mehdi Karoubi said he and the president were in contact with the Guardians Council and Ayatollah Khamenei.

Calling on those rejected to "lodge a formal complaint", Karoubi said reformers had several channels and time to reverse the decision before a definitive list is published 10 days before the vote.

"We hope that through negotiations we can obtain the approval of a certain number of rejected candidates, but not all of them," said the speaker, a reformer close to the president who has not been barred.

The Guardians' Council is a senate-like body that vets all Majlis legislation to see if it complies with Islamic law and the constitution.

Dominated by conservatives and religious hardliners - all at odds with the reformist bid to shake up the way the 25-year-old Islamic republic is run and directly or indirectly appointed by Khamenei - it has binned scores of bills passed by parliament since reformists won the last legislative elections in 2000.

The body also has the highly contested right, through its electoral vetting arm, to screen candidates for public office. The parliament has tried but failed to end this power after hundreds of reformists were barred from past polls.

According to reformist sources, this time the Guardians Council had systematically rejected reformists. In some areas, notably the northeastern city of Mashhad, all reformists had been struck off the voting lists and only conservatives were left.

Left contesting Tehran's 30 seats, for example, are just 10 reformists. According to reports, the number of disqualified candidates numbered up to half of the 8,149 people who registered with the interior ministry last month to stand in the elections.

And of the 210 reformists currently in the 290-seat Majlis, 85 have seen their candidacies rejected, including Behzad Nabavi, who along with the president's brother is a deputy Majlis speaker.

Also believed to have been rejected were outspoken leftist Mohsen Armin and female MP Elaheh Koulaiee, who is close to Nobel Peace laureate Shirin Ebadi's campaign for women's rights.-AFP