Moderates and reformists have dealt another blow to Iran's hardliners, winning all but one of the seats for Tehran in the Assembly of Experts.
President Hassan Rouhani and his allies won 15 out of the capital's 16 seats on the clerical body, which may choose the country's next supreme leader.
Two leading hardline clerics, assembly chairman Mohammad Yazdi and Mohammad-Taqi Mesbah-Yazdi, lost their seats.
The only hardliner to make the cut in Friday's polls was Ahmad Jannati.
The vote for the 88-member Assembly of Experts was held on the same day as the country's parliamentary elections, in which moderates and reformists won all 30 of Tehran's seats.
Partial results from elsewhere in the country are mixed, with hardliners so far winning 153 seats in the 290-seat parliament and moderates and reformists 111.
The final results of that vote are expected later on Monday.
More than 30 million Iranians voted in Friday's polls, the first since the implementation of a landmark nuclear agreement between world powers and Iran that saw it curb sensitive nuclear activities in return for the lifting of sanctions.
The deal was opposed by many hardliners but backed by moderates and reformists, who for the first time formed combined electoral lists and asked their supporters to vote tactically in an effort to increase their shares of the seats in parliament for the next four years and in the Assembly of Experts for the next eight.
Analysis: Lyse Doucet, BBC News international correspondent
This stunning election result will make a difference in Iran's engagement with the wider world.
President Rouhani's hand has been strengthened in parliament to help open his country to greater trade and investment. That will help him, and others in his reformist camp, to deepen the dialogue with the West, which began with negotiations on a landmark nuclear deal.
But much of this opening will continue to be with Europe, rather than the US. Iran's relationship with America is still complex and controversial.
Iran's ambitions in the region are also deeply rooted - it has strategic interests in countries like Syria, Iraq and Lebanon as well as Afghanistan, and a strong sense of its right to remain engaged. These are areas where Iran's powerful Revolutionary Guards and its conservative Supreme leader hold sway.
But Iran wants to be regarded as an equal partner, able to sit at the world's top tables to work on common threats like the so-called Islamic State. President Rouhani's team may now feel empowered to engage a bit more, more often.
One goal they set was to unseat the three leading hardliners on the clerical council.
In the end, only Ayatollah Jannati - who is also the leader of the Guardian Council, an unelected body disqualified thousands of reformist candidates from standing on Friday - managed to win re-election in Tehran.
On Sunday, as it became clear that Ayatollah Yazdi and Ayatollah Mesbah-Yazdi were going to lose their seats, the head of the judiciary complained of foreign interference.
Ayatollah Sadeq Larijani alleged that moderates and reformists had formed "a British list" and worked with "American and English media outlets" during the election campaign.
"Is this type of co-ordination with foreigners in order to push out these figures from the Assembly of Experts in the interests of the regime?" he asked.
Mr Rouhani and his allies have rejected such accusations.
"We don't have anything such as a 'British list' and if anyone wants to say that there is such a list, they are in fact insulting the Guardian Council," said Vice-President Mohammad Baqer Nobakht.
The new composition of the Assembly of Experts is seen as significant given that Supreme Leader Ayatollah Ali Khamenei is 76 and has suffered ill-health.
The president has portrayed the election results as an endorsement of his efforts to end Iran's international isolation.
"It's time to open a new chapter in Iran's economic development based on domestic abilities and international opportunities," he said on Saturday.
BBC Persian's Ali Hamedani says the economy was a key issue in the election. With sanctions lifted and Western investors beginning to return to Iran, there are high hopes for an improvement in daily life, our correspondent reports.