Conservative rivals of Iran's hardline president, Mahmoud Ahmadinejad, were leading the race for seats in parliament, according to initial results yesterday from Friday's elections that the reformist movement shunned as a sham.
The trend, if confirmed by final official results, will leave the president facing a more hostile house during his remaining 18 months in office.
Analysts had predicted a strong showing by Mr Ahmadinejad's hardline opponents. They are loyal to Iran's supreme leader, Ayatollah Ali Khamenei, who has been locked in a power struggle with the unruly president he once championed.
Mr Ahmadinejad had hoped a robust performance by his candidates would give him a political lifeline and a say in who succeeds him in the presidential election next year when his second term ends.
But out of 189 winners declared by noon yesterday, at least 97 were conservative opponents of the president, the Associated Press reported. Also elected were six liberal-leaning candidates opposed to him. The remaining 86 seats were split between the president's supporters and centrists.
In a particular embarrassment, Parvin Ahmadinejad, his younger sister, was defeated by a conservative in their hometown of Garmsar, Iran's semi-official Mehr news agency reported.
Whatever the complexion of the new 290-seat parliament, internecine fighting among Iran's ruling hardliners appears set to continue.
The president, as pugnacious as he is populist and polarising, will not see out his second and final four-year term without a fight, many experts said.
"Ahmadinejad and his friends will not step aside quietly," said a political analyst in Tehran who requested anonymity.
The fractious regime as a whole expressed delight with "epic" voter turnout, which officials said initial estimates showed to be about 65 per cent, almost 10 per cent more than the last parliamentary elections in 2008.
State media trumpeted this as a "great slap in the dirty and hateful face of the West", declaring the "enemy" had been left "disappointed and angry".
According to Iran's official narrative, the Islamic republic's western foes and Israel had hoped for a low turnout that would weaken the regime, making it easier to pressure Tehran over its nuclear programme.
But with no independent monitors, it was impossible to confirm the turnout which the regime views as a popular endorsement of its legitimacy.
The vote was only a limited test of political opinion since leading reformist groups either boycotted the election or were banned from competing.
Moreover, all candidates were screened for their loyalty to the Islamic establishment by an unelected, hardline vetting body controlled by Ayatollah Khamenei.
Britain's foreign secretary, William Hague, said the election was not free or fair.
"The regime has presented the vote as a test of loyalty, rather than an opportunity for people to freely choose their own representatives," he said.
Iranian media reported Ali Larijani, the speaker of the outgoing parliament and a bitter opponent of the president, had scored a big victory in Qom.
Gholam Ali Haddad Adel, a former parliamentary speaker whose daughter is married to one of the supreme leader's sons, was leading in Tehran, followed by other Khamenei loyalists.
Ali Mottahari and Ahmad Tavakoli, two high-profile conservative opponents of the president, also appeared to be heading for a win in the Iranian capital.
Mr Mottahari led the drive to summon Mr Ahmadinejad before parliament for a grilling on his handling of the economy and other issues.
He is due to appear before the outgoing house within days, an unprecedented humiliation for an incumbent president, although the resilient Mr Ahmadinejad may well use the platform to hit back hard at his opponents. He is said to have collected intelligence files on his rivals, detailing their alleged involvement in corrupt deals.
A reformist former president, Mohammad Khatami, was meanwhile lambasted by fellow reformists for casting his vote on Friday. His sister-in-law, Zahra Eshraghi, described it as a "severe blow".
Among other stipulations, Mr Khatami had said there should be no participation unless political prisoners were freed, including the two leaders of the opposition Green Movement, Mir Hossein Mousavi and Mehdi Karrubi, who have been under house arrest for a year.
State-run media seized upon Mr Khatami's ballot as proof of the regime's legitimacy.
Another former president critical of the regime, Ayatollah Ali Akbar Rafsanjani, also cast his ballot but made a barbed allusion to the alleged vote-rigging that returned Mr Ahmadinejad to power in June 2009.
"God willing, the election result is what the people want and what they voted for," he said.