Moderate conservative Ali Larijani retained the speakership of Iran's parliament on Sunday despite major gains for reformists in February elections, benefiting from credit gained by his support for last year's nuclear deal.
Several lawmakers from the reformist camp broke ranks to vote against the head of their own List of Hope, Mohammad Reza Aref, who lost by 103 votes to 173.
February's election was widely seen as a referendum on last July's nuclear deal with world powers led by the United States, the signature policy of moderate President Hassan Rouhani.
Larijani's support for its passage through parliament kept him out of the fierce debate that saw a string of hardline opponents of the agreement lose their seats.
Reformists took 133 of the 290 seats in parliament. That fell short of a majority but it was more than the conservatives' 125 seats.
The remaining seats are held by independents and representatives of religious minorities who are expected to give Rouhani a working majority to pass key reform legislation that eluded him in the outgoing conservative-dominated parliament.
Several leading reformists broke ranks to endorse Larijani in the runup to the speakership contest.
"Larijani can better direct parliament than Aref," Gholam Hossein Karbaschi, the leader of one reformist faction, the Construction Party, told the Shargh
newspaper on Tuesday.
Praise from president
Rouhani himself praised Larijani and his support for the nuclear deal in an address to the opening session of parliament on Saturday.
"We need interaction to solve the problems and crises of the country," he said, adding that February's poll gains for his supporters were a vote for an end to international sanctions imposed over Iran's nuclear programme and an improved standard of living.
Rouhani is president but ultimate power in Iran rests with supreme leader Ayatollah Ali Khamenei who called on the new parliament to remain faithful to the principles of the Islamic revolution of 1979 that saw relations with Washington ruptured the following year.
Using the term "arrogance" first coined to refer to the United States by his predecessor, revolutionary leader Ayatollah Ruhollah Khomeini, Khamenei urged lawmakers to be wary of its schemings.
"It is the revolutionary and legal duty of you to make the parliament a stronghold against the schemes, charms and impudently excessive demands of the arrogance," he said in a message read to the packed opening session.
Khamenei has said repeatedly that the nuclear deal with Washington, which he finally endorsed, was a one-off and that it should not lead to a generalised rapprochement with the West.
Despite their heavy defeat in February's elections, hardline opponents of the nuclear deal still control most of the principal levers of power in the Islamic republic.
On Tuesday, Ayatollah Ahmad Jannati, an arch-conservative who scraped re-election at the ballot box in 16th place in Tehran, was chosen by fellow clerics as chairman of the Assembly of Experts, the body that oversees Khamenei's work.
The assembly would also elect Khamenei's successor if the 76-year-old dies during its eight-year term.
Jannati already chairs the Guardian Council, the body which vets all candidates for public office in Iran and has a veto over all legislation.
The council sparked controversy in February's election by disqualifying thousands of hopefuls, most of them reformists.