Reformist allies of moderate President Hassan Rouhani won all 30 parliamentary seats in the Iranian capital, a major boost today that pushed them into a nationwide lead in crucial elections.
Combined with results coming in from more than half the 290 seats up for grabs nationwide from Friday's polls, the pro-Rouhani List of Hope was outpacing its conservative rivals overall.
A clean sweep in Tehran was followed by steady gains elsewhere, according to preliminary results, in a major fillip for the president, signalling overwhelming public backing for his landmark nuclear deal with world powers last year that ended a 13-year standoff.
The election outcome is vital to Rouhani's chances of introducing domestic reform in the form of legislation capable of delivering even limited social, political and economic changes.
The coalition of moderates and reformists representing the president's hopes was on course to wipe out conservatives in Tehran with 90 per cent of ballots counted.
In comments posted on Twitter beside a picture of smiling voters, young and old, he said: "With your skilful voting you've created a new atmosphere. In respect, I stand up before you, great nation, who are the pride of the history of the land of Iran."
The polls are Iran's first since sanctions were lifted last month under the nuclear agreement, which included unprecedented talks with the US, the Islamic republic's bete noire since a revolution in 1979 overthrew a US-backed monarchy.
A rout in Tehran was completed when state television said the head of the conservative list, Gholam-Ali Hadad Adel, a former parliament speaker, was in 31st place and set to lose.
Elsewhere, where 135 seats out of 260 have been declared so far, 38 went to the main conservative list and 30 to the List of Hope. A further 36 seats went to independents -- of whom 16 are known to lean towards conservatives and 13 are close to reformists, with the others of no clear affiliation.
None of the remaining 31 seats had a clear winner, meaning a second round of voting will be needed, which is not expected until April or May.
Preliminary results from second poll, for the powerful Assembly of Experts which monitors the work of supreme leader Ayatollah Ali Khamenei, were also heading Rouhani's way, and could see top conservative clerics eliminated.
Turnout in the election was solid at 60 percent, but slightly less than the 64 percent of 2012.
Conservatives were also experiencing setbacks in the election to the Assembly of Experts, an 88-member group of clerics that would pick Khamenei's successor if he dies in the next eight years.
Two of three ayatollahs that the pro-Rouhani list had urged voters to reject -- Ahmad Jannati, Mohammad Yazdi and Mohammad Taghi Mesbah-Yazdi -- were set to lose their seats.
Only Jannati, who chairs the conservative-dominated Guardian Council which must confirm the results of both elections, was safe.
Rouhani and his close ally Ayatollah Hashemi Rafsanjani, a former two-term president, held third and first places.
