Iranian Foreign Minister Mohammad Javad Zarif submitted on Monday his resignation, making the surprise announcement on Instagram.
A Foreign Ministry spokesman, Abbas Mousavi, confirmed to the state-run IRNA news agency minutes later that Zarif had resigned but gave no reason for his departure.
There was no immediate word, however, on whether President Hassan Rouhani would accept it.
On Tuesday, Zarif said fighting between parties and factions in Iran is a “deadly poison” undermining foreign policy.
“We first have to remove our foreign policy from the issue of party and factional fighting,” Zarif told the Jomhuri Eslami newspaper. “The deadly poison for foreign policy is for foreign policy to become an issue of party and factional fighting.”
His comments suggest he may have quit over pressure from hardline elements who have long criticized his role in negotiating the 2015 nuclear deal with world powers.
The Fars news agency reported that the interview had taken place last week, before the resignation.
Unconfirmed media reports indicated he resigned over Syrian regime chief Bashar Assad’s visit to Tehran on Monday. Noting that Zarif was not pictured in any of the coverage of the visit, one online website said “the foreign minister was not informed”.
“Many thanks for the generosity of the dear and brave people of Iran and its authorities over the past 67 months. I sincerely apologize for the inability to continue serving and for all the shortcomings during my service. Be happy and worthy”, he wrote on his Instagram page jzarif_ir.
On Sunday, Zarif criticized Iranian hardliners in a speech in Tehran, saying: "We cannot hide behind imperialism's plot and blame them for our own incapability."
"Independence does not mean isolation from the world," he said.
Several lawmakers and politicians took to social media calling on the pragmatist Rouhani to reject the resignation, saying it would not serve national interests and would empower hardliners in Iran’s faction-ridden clerical establishment.
A prominent reformist lawmaker, Mostafa Kavakebian, wrote on Twitter that Rouhani should reject Zarif's resignation as his departure would only "make enemies of Iran's dignity happy."
A majority of Iran’s lawmakers signed a letter to Rouhani on Tuesday, asking for Zarif to continue his job, Ali Najafi Khoshroodi, the spokesman for the parliament’s National Security and Foreign Policy commission told IRNA.
Zarif urged diplomats and other employees at the foreign ministry not to quit on Tuesday, according to IRNA.
Hassan Mohammadi, a Tehran-based political analyst close to Rouhani, said he understood it was Zarif's third time submitting his resignation in the last year.
"It is part of plan for changing the track in foreign policy in Iran. A negotiation-seeking foreign minister is not a favored person anymore," Mohammadi told The Associated Press. "Iran needs a tough foreign minister from now on. Someone who does not offer smile towards the West."
US Secretary of State Mike Pompeo, in a post on Twitter, dismissed Zarif and Rouhani as “front men for a corrupt religious mafia.”
“Our policy is unchanged - the regime must behave like a normal country and respect its people”, Pompeo said.
Born in 1960, Zarif lived in the United States from the age of 17 as a student in San Francisco and Denver, and subsequently as a diplomat to the United Nations in New York, where he served as Iranian ambassador from 2002-07.
He was appointed minister of foreign affairs in August 2013 after Rouhani won the presidency in a landslide on a promise to open up Iran to the outside world.
Since taking charge of Iran’s nuclear talks with major powers in late 2013, Zarif has been summoned to parliament several times by hardline lawmakers to explain the negotiations.
Some hardliners even threatened Zarif with bodily harm after the nuclear deal was signed. Supreme leader Ali Khamenei guardedly backed the deal, under which Iran agreed to curb its nuclear work.
