Iran said has said it will not be rushed into a "quick" deal to revive the abandoned nuclear accord it signed with world powers in 2015, as negotiations remain deadlocked.
Foreign Ministry spokesman Nasser Kanani said Tehran will "not sacrifice the country's fundamental interests with a rushed process".
"They demand that Iran makes a quick decision, [insisting that] time is limited and Iran must respond quickly," Mr Kanani told reporters, referring to western parties to the nuclear deal.
The Islamic republic is being put under "psychological pressure and unilateral expectations", he said.
But "if the US acts constructively and positively, an agreement is close", the spokesman said.
Mr Kanani's remarks came after Raphael Grossi, head of the International Atomic Energy Agency, reiterated in an interview with CNN the UN nuclear watchdog's assessment that Iran's nuclear programme was "galloping along."
He stressed however, that his organisation was impartial when evaluating Iran's nuclear programme.
"We report the nuclear activities of the country and how they are progressing. As we speak, Iran continues to enrich more and more uranium at a very high level of isotopic enrichment," Mr Grossi said.
"Iran is putting together, manufacturing last-generation centrifuges, which are necessary to enrich this material. So, what we are saying is just an objective description of the facts."
Mr Grossi also said there was a difference between being close to weapons-grade uranium enrichment and actually creating a long range nuclear weapon delivery system.
One challenge for Iran, experts say, is known as "warhead miniaturisation," the technical feat of fitting a warhead on a missile, but one that countries such as North Korean still achieved, shocking the world with a nuclear test in 2006.
"I should stress, we do not have information that they are making nuclear weapons," he said, before warning that the level of uranium enrichment was “close to weapons grade”.
The 2015 deal gave Iran sanctions relief in exchange for restrictions on its atomic programme, to guarantee that it would not develop a nuclear weapon ― something that the country has always denied seeking.
But the unilateral withdrawal by the US from the accord in 2018 under former president Donald Trump ― and Washington's reimposition of biting economic sanctions ― prompted Iran to begin rolling back on its own commitments.
Talks in Vienna that started in April 2021 to restore the deal have stalled since March amid differences between Tehran and Washington on several issues.
The two sides negotiated indirectly through EU co-ordinators.
Qatar hosted indirect talks last month between the US and Iran, in a bid to get the Vienna process back on track, but those discussions broke up after two days without any breakthrough.
On Thursday, US State Department spokesman Ned Price said Iran "doesn't seem to have made the political decision ― or decisions, I should say ― necessary to achieve a mutual return to compliance" with the deal.
Tensions have also risen over Iran's non-compliance with nuclear commitments it made to world powers.
In June the UN's International Atomic Energy Agency said Iran was removing 27 surveillance cameras at its nuclear installations, as the IAEA passed a resolution censuring Tehran over its lack of cooperation.
On Monday the head of Iran's nuclear organisation, Mohammed Eslami, said the cameras would not be reconnected until after the relaunch of the nuclear deal.
He said the cameras were aimed at showing that the West's claims that Iran is seeking "an atom bomb" are baseless.
"If these claims are maintained, there is no reason to have cameras," Mr Eslami said.
French President Emmanuel Macron on Saturday told his Iranian counterpart Ebrahim Raisi that reviving the deal was "still possible" but must happen "as soon as possible".
Mr Macron's comments came after Britain's spy chief voiced doubt that the deal can be revived, saying Iran's supreme leader and ultimate decision-maker Ayatollah Ali Khamenei remained opposed.
"I don't think the supreme leader... wants to cut a deal. The Iranians won't want to end the talks either so they could run on for a bit," MI6 chief Richard Moore said late last week.