Ali Akbar Salehi, who runs the Iranian nuclear programme, said that should the country decide to relaunch its nuclear programme it could enrich uranium up to ten times faster than its previous rate.
He claimed that since President Trump’s withdrawal from the Iran nuclear deal in May, Iran has extended its Natanz enrichment centre so it can build more advanced centrifuges, though it has not done so yet.
Mr Salehi warned: “If we have to go back and withdraw from the nuclear deal, we certainly do not go back to where we were before.
“We will be standing on a much, much higher position.”
He added that the expanded facility “does not mean that we are going to produce these centrifuges now”.
He noted: “This is just a preparation.
“In case Iran decides to start producing such centrifuges in mass production, we would be ready for that.”
The Iranian government remains officially committed to the nuclear deal, which was signed alongside major powers in July 2015.
Ali Larijani, the powerful speaker of Iran’s parliament, claimed this week that the country will honour the deal.
He said Iran currently operates between 3,000 and 4,000 active centrifuges, below the limit of 5,060 which the deal allows.
Prior to the 2015 deal, Iran reportedly had 20,000 centrifuges installed.
Trump withdrew the US from the nuclear deal in May, claiming it didn’t stop Iran developing ballistic missiles or supporting terror groups across the Middle East.
The other signatories of the deal — China, Russia, France, Germany, the UK and the EU — are attempting to save the accord.
In August, the US reimposed economic sanctions on Iran, with another batch scheduled to take effect in November.
Since then the value of the Iranian currency against the dollar has halved.
The US has also accused Iran of failing to prevent a mortar attack on its Baghdad embassy last week, which it alleges was carried out by an Iranian supported group.
The Iranian Foreign Minister hit back, describing the accusation as “provocative and irresponsible”.