DUBAI: A mysterious explosion and fire at Iran's main nuclear facility may have stopped Tehran from building advanced centrifuges, but it likely has not slowed the Islamic Republic in growing its ever-increasing stockpile of low-enriched uranium.
Limiting that stockpile represented one of main tenets of the nuclear deal that world powers reached with Iran five years ago this week - an accord which now lies in tatters after President Donald Trump unilaterally withdrew America from it two years ago.
The larger that stockpile grows, the shorter the so-called "breakout time" becomes time that Iran would need to build a nuclear weapon if it chooses to do so.
And while Tehran insists its atomic program is for peaceful purposes, it has renewed threats to withdraw from a key nonproliferation treaty as the US tries to extend an UN arms embargo on Iran due to expire in October.
All this raises the risks for further confrontation in the months ahead.
Iranian officials likely recognized that as they realized the scope of the July 2 blast at the Natanz compound in Iran's central Isfahan province.
They initially downplayed the fire, describing the site as a "shed" even as analysts immediately told The Associated Press that the blast struck Natanz's new advanced centrifuge assembly facility.
Days later, Iran acknowledged the fire struck that facility and raised the possibility of sabotage at the site, which was earlier targeted by the Stuxnet computer virus.
Still, it has been careful not to directly blame the U.S. or Israel, whose officials heavily hinted they had a hand in the fire.
A claim of responsibility for the attack only raised suspicions of a foreign influence in the blast.
A direct accusation by Tehran would increase the pressure on Iran's Shiite theocracy to respond, something it apparently does not want to do yet.
The explosion and fire, however, did not strike Natanz's underground centrifuge halls.
That's where thousands of first-generation gas centrifuges still spin, enriching uranium up to 4.5 per cent purity.
Meanwhile, enrichment also has resumed at Iran's Fordo nuclear facility, built deep inside a mountain to protect it from potential airstrikes.
Iran continues to experiment with previously built advanced centrifuges as well.
The explosion "at Natanz was above all a blow to Iran's plans to move on to more advanced stages in its nuclear project," wrote Sima Shine, the head of the Iran programme at the Institute for National Security Studies in Israel who once worked in the country's Mossad intelligence service.