Iran's hardline council of guardians today reversed its ban on two reformist candidates seeking to stand in the country's presidential election.
The move came after Iran's supreme leader, Ayatollah Ali Khamenei, made an unexpected intervention on behalf of the two men.
The council - an unelected body of conservative clerics and judges - said it had reinstated the candidacies of the former education minister Mostafa Mo'ein and Mohsen Mehralizadeh, the vice-president for sport.
Its decision is expected to neutralise reformist calls for a boycott of the June 17 elections, which could have severely dented voter turnout. It came hours after the ayatollah urged the council to reconsider its exclusion of all but six of the 1,014 people hoping to run in the election.
Of the six candidates approved by the council, five were hardline conservatives. The former president Hashemi Rafsanjani - a moderate conservative who is considered to be the election frontrunner - was also approved. He supports economic liberalisation and closer relations with the west.
However, the threat of a boycott sparked fears voter turnout could fall so low that it would call into question the legitimacy of Iran's clerical government. Since the Islamic revolution in 1979, voter turnout has always been above 50%.
In a decree read on Iranian state television last night, the ayatollah said: "It is appropriate that all individuals in the country be given the choice from various political tendencies. Therefore it seems that the qualification of Mr Mo'ein and Mr Mehralizadeh should be reconsidered."
His statement could have been intended to ensure that reform-minded voters went to the polls, and he may also have been hoping that voters likely to support Mr Mo'ein would take backing away from Mr Rafsanjani, whose policies Mr Khamenei opposes.
Mr Mo'ein is an outspoken reformist who has promised to tackle human rights abuses, while Mr Mehralizadeh is not considered to be a serious contender.
Tehran University students, long at the forefront of the reform movement, demonstrated their anger last night, with between 100 and 150 students shouting "down with dictators" from their dormitories. Such scenes have in the past been the prelude to bitter clashes with the authorities.
Mr Mo'ein's reinstatement could offer reformists an opportunity to retain the presidency, which has been held by the pro-reform cleric, Mohammad Khatami, since 1997. Mr Khatami is ineligible to run for a third consecutive term.