Iran on Saturday (local time) said that it would begin increasing its urum stockpile limit to five per cent at one of its main underground facilities, sparking new criticisms by major powers after a series of steps back from its commitments under the troubled 2015 nuclear deal.
The deal four years ago had set a 3.67 per cent limit for urum enrichment that was dismissed by Tehran after Washington unilaterally abandoned the agreement last year and reimposed crippling sanctions that hampered the country's economy and foreign assets, Al Jazeera reported.
"Based on our needs and what we have been ordered, we are currently producing five per cent," said Behrouz Kamalvandi, a spokesman for the Atomic Energy Orgsation of Iran.
He also said that Iran has the "capacity to produce five per cent, 20 per cent, 60 per cent, or any percentage" of enriched urum, a claim that has often been repeated by Tehran.
Urum enrichment is a sensitive process that produces fuel for nuclear power plants but also, in highly extended form, the fissile core for a warhead.
The current five per cent-level exceeds the limit set by the accord but is less than the 20 per cent Iran had previously operated and far less than the 90 per cent level required for a warhead.
In its fourth step away from the agreement, Iran resumed enrichment at the Fordow plant south of Tehran on Thursday, with engineers feeding urum hexafluoride gas (UF6) into the plant's mothballed enrichment centrifuges.
Iran was already enriching urum at another plant in Natanz, where a United Nations inspector was denied access to the site last week.
Tehran says it would reverse the measures it has taken if the remaining member nations of the 2015 nuclear accord, including the United Kingdom, China, France, Germany and Russia, find a way to get around US sanctions.
On July 1, Iran said it had increased its stockpile of enriched urum to beyond a 300-kilogramme limit set by the deal, and a week later, it announced it had exceeded the enrichment cap.
The third move had it firing up advanced centrifuges on September 7 to enrich urum faster and to higher levels.
( With inputs from ANI )