Iran's Interior Ministry, faced with a confrontation between reformists and hard-liners over next month's parliamentary elections, said on Saturday it would hold the vote only if satisfied that candidates had not been unfairly barred.
But the ministry, under the authority of President Mohammad Khatami's reformist government, stressed that if it withdrew, the elections would not be postponed as "senior officials" would appoint another body to oversee the voting.
The Guardian Council, a conservative watchdog, has blocked almost half of 8,200 parliamentary hopefuls from February's vote, including 80 of the standing 290 MPs.
"We do not have the right to postpone the elections," said Morteza Mobalegh, head of the electoral board at the Interior Ministry.
"We are trying to restore the rights of all aspiring candidates but if we cannot hold a free and legal vote, we will not hold this election," he added.
When asked who would oversee the elections if the Interior Ministry pulled out, he replied: "Then senior officials will decide".
The Interior Ministry joins a chorus of dissenters keen to distance themselves from an election liable to be slammed as illegal and undemocratic by the international community.
Several government ministers and provincial governors have threatened to resign.
Iranian MPs, protesting about the disqualifications at a parliamentary sit-in headed towards its seventh night, started a political fast on Saturday, abstaining from food and drink during daylight hours.
These staged fasts are a common and largely ineffective facet of Iranian political life.