Iran has threatened to restart deactivated centrifuges and sharply step up its enrichment of uranium to 20 per cent purity as its next potential big moves away from a 2015 nuclear agreement that Washington abandoned last year.
The threats, made by the spokesman for Iran's nuclear agency, would go far beyond the small steps Iran has taken in the past week to nudge its stocks of fissile material just beyond limits in the nuclear pact.
That could raise serious questions about whether the agreement, intended to block Iran from making a nuclear weapon, is still viable.
Behrouz Kamalvindi, spokesman for Iran's Atomic Energy Organisation, confirmed an announcement that Tehran had enriched uranium beyond the 3.67 per cent purity that the deal allows, passing 4.5 per cent, according to the student's news agency INSA.
That followed an announcement a week ago that it had amassed a greater quantity of low-enriched uranium than permitted.
Iran has said it will take another, third step away from the deal within 60 days but has so far held back from formally announcing what that next step would entail.
Kamalvindi said the authorities were discussing options that included the prospect of enriching uranium to 20 per cent purity or beyond, and restarting centrifuges that were dismantled as one of the deal's core aims.
Such threats will put new pressure on European countries, which insist Iran must continue to comply with the agreement even though the United States is no longer doing so.
Washington has imposed sanctions that eliminate any of the benefits Iran was meant to receive in return for agreeing to curbs on its nuclear program under the 2015 deal with world powers.
The confrontation has brought the United States and Iran close to the brink of conflict, with President Donald Trump calling off air strikes last month minutes before impact.
The nuclear diplomacy is only one aspect of a wider confrontation between Washington and Tehran that has threatened to spiral into open conflict since the United States sharply tightened sanctions on Iran from the start of May.
Last month, President Donald Trump ordered US air strikes on Iran, only to call them off minutes before impact. Washington's European allies have been warning that a small mistake on either side could lead to war.
