A group of 120 Iranian reformist members of parliament submitted resignations on Sunday to parliament or Majlis speaker Mahdi Kharubi. The resignations were effective immediately.
In a joint statement read out by prominent reformist MP Muhsin Mirdamadi, the deputies said they "cannot continue to be present in a parliament that is not capable of defending the rights of the people and which is unable to prevent elections in which the nation cannot choose their representatives."
"They are in the process of removing the republican aspect from the Islamic republic, and installing an Islam comparable to that of the Taliban," the statement said in a cutting comparison of Iranian conservatives to Afghanistan's ousted Taliban group.
It was read live on national radio during a stormy session.
The hardliners behind the mass barring of election candidates from the 20 February polls were also labelled as "traitors".
In a symbolic move, the resignations coincided with the hour and day of the return from exile 25 years ago of Iran's revolutionary leader Ayat Allah Ruhollah Khomeini.
The crisis was sparked when the 12-member Guardians Council, an unelected body that screens all laws and candidates for public office, barred thousands of candidates from contesting the polls. Most of those disqualified are reformists.
Kharubi appealed for Iran's supreme spiritual leader Ayat Allah Ali Khamenei to intervene in the country's political crisis.
Iran's Majlis speaker Mahdi
Kharubi warns of a deadlock
"We are in a deadlock," said the pro-reform Majlis speaker.
Khamenei has the final say on all matters of state, and he directly or indirectly appoints all members of the Guardians Council.
The supreme leader had already intervened in the bitter crisis, by telling the Guardians Council to be less stringent.
Iranian political analyst Muhammad Sadiq al-Husayni told Aljazeera Khamenei had not stepped in more because he was hoping the two sides could reach an agreement.
Kharubi had also expressed his solidarity with the MPs who resigned, said al-Husayni. The Majlis speaker believes conservatives have lost public support and want to strongarm their way back into parliament through the Guardian Council's ban, he added.
But the body has stood by its ban on nearly 2500 out of about 8000 candidates from the elections. Among those barred are 87 incumbent MPs, including top leaders of the reformist movement and allies of embattled President Muhammad Khatami.
The government has already refused to organise the elections.
The resignations will deny the 290-member Majlis of its required two-thirds quorum for future sessions, effectively paralysing pending national legislation such as budget.