Iran's chief negotiator Mohammad Bagher Ghalibaf said on Friday that talks with the United States would remain bound by Tehran's "red lines".
"As we have shown in the past path of negotiations, we are steadfast in fulfilling the conditions and red lines set, and in achieving the interests of the Iranian nation," Ghalibaf said in remarks published by the official IRNA news agency.
"If the enemy seeks to be excessive, we have proven that our fingers are on the trigger and we have no hesitation in giving a crushing response to the enemy."
Tehran and Washington signed a memorandum of understanding this week ending a regional war that erupted on February 28 with US-Israeli strikes on Iran.
Ghalibaf's remarks came after Iran's supreme leader Mojtaba Khamenei said he had approved the US-Iran deal despite having a "different view" on the matter, without elaborating.
In a message read out on state television, Khamenei said that direct talks with the United States "will not mean accepting the enemy's point of view".
In response to Khamenei's message, Foreign Minister Abbas Araghchi said the country's foreign policy apparatus "will be used to secure the sublime interests of Iran" and "protect the rights of the noble Iranian nation".
President Masoud Pezeshkian, who signed the deal on behalf of his country, issued a similar statement promising to adhere to Iran's red lines and defend its "dignity, honor and authority".
The US-Iran deal, which US President Donald Trump also signed, lays the groundwork for detailed 60-day negotiations on Iran's nuclear program and sanctions relief.
It remains unclear when talks for a final settlement would start after a first meeting in Switzerland slated for Friday was postponed.
The agreement provides for an end to the Middle East war on all fronts, including Lebanon, the lifting of the two-month US naval blockade on Iranian ports, and Tehran's reopening of the Strait of Hormuz "with no charge for 60 days only".
It also includes an Iranian commitment not to procure or develop nuclear weapons -- an ambition Tehran has consistently denied pursuing.
Conservatives in Iran appeared deeply skeptical of the deal and US intentions, with some expressing concern that Tehran could be giving up key sources of leverage before securing compensation and sanctions relief.
"The Americans do not honor to any commitments, they have not been loyal to any agreements, and they will not be," said Hossein Shariatmadari, editor-in-chief of the ultraconservative Kayhan newspaper, in an interview with state television on Thursday.
He added: "The Strait of Hormuz is the way to get compensation."
Ebrahim Rezaei, spokesman for parliament's national security commission, took issue with reports of possible inspections of Iranian nuclear facilities by a UN watchdog.
"I hope the government denies this, but if this claim is true... the parliament will stand up to lawlessness and disobedience," he said in a post on X.
