Tehran and Washington have doubled down on threats, waging a war of words, ahead of key talks in Oman, after US President Donald Trump once again said military action was on the table if the talks failed.
A senior adviser to Iran's supreme leader Ayatollah Ali Khamenei warned that Tehran could expel UN nuclear watchdog inspectors over "threats" before Saturday's talks.
"The continuation of external threats and Iran being in a state of military attack may lead to deterrent measures, including expulsion of inspectors from the International Atomic Energy Agency and cessation of co-operation," Rear Admiral Ali Shamkhani said on X.
"Transfer of enriched materials to secure locations may also be considered," he added, referring to the Iran's uranium enrichment.
His comments came after Mr Trump on Wednesday repeated his threat to use military force if Iran did not agree to end its nuclear programme, saying Israel would play a key role. He reaffirmed that Iran could not be allowed to have a nuclear weapon.
“If necessary, absolutely ... if it requires military, we’re going to have military,” Mr Trump said. "Israel will obviously be very much involved in that. They’ll be the leader of that. But nobody leads us, but we do what we want to do."
Washington warned Tehran against expelling nuclear inspectors. "The threat of that kind of action, of course, is inconsistent with Iran's claims of a peaceful nuclear programme," State Department spokeswoman Tammy Bruce said. "Also, expelling IAEA inspectors from Iran would be an escalation and a miscalculation on Iran's part."
The threats are a further sign of the difficult path ahead to reach a deal between the two countries. Iranian Foreign Minister Abbas Araghchi and Mr Trump's Middle East envoy Steve Witkoff will represent their countries during the talks, which are to be mediated by Oman.
On Friday, Mr Shamkhani said on X that Mr Araghchi was heading to Oman with "full authority" for indirect talks with the US. "Key proposals are ready. If Washington shows determination for a deal, the path to agreement will be clear," he said.
In 2015, world powers, including the US, signed a deal with Iran that put limits on its nuclear programme in exchange for sanctions relief. Mr Trump withdrew the US from the deal during his first term in office and instituted a “maximum pressure” economic campaign against Iran, which he reinstated when he returned to the White House this year.
The policy has been carried out through sanctions on Iranian interests, as well as military action against Iranian proxies such as the Houthi rebels in Yemen.
In a mainly symbolic move, the US Treasury Department said it was imposing sanctions under additional authorities on five entities, including the Atomic Energy Organisation of Iran and one individual.