Iran's enriched uranium and heavy water stocks grew but did not exceed the ceilings set in the 2015 agreement, the UN's nuclear watchdog agency, the International Atomic Energy Agency (IAEA), wrote in a quarterly report published Friday.
As of May 26, Iran had 125.2 metric tons of heavy water, an increase of 0.4 tons on February but still under the 130-ton limit, said the Vienna-based IAEA.
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As of May 20, Iran had 174.1 kilograms of enriched uranium, up from 163.8 kilograms in February but again below the relevant of limit 300 kilograms, it added.
The IAEA report flagged a number of more advanced Iranian centrifuges — used to enrich uranium — saying the IR-6 models installed could become a potential issue.
"Technical discussions in relation to the IR-6 centrifuges are ongoing," it said.
German diplomat visits Tehran
Iranian President Hassan Rowhani on May 8 threatened a gradual exit from the deal and gave major powers, including Germany and China, until early July to persuade US President Donald Trump's administration to lift oil and banking sanctions.
On Thursday, Germany sent senior diplomat Jens Plötner to Tehran to help try to salvage the deal.
"The situation in the Persian Gulf and the region, and the situation surrounding the Vienna nuclear agreement is extremely serious," said the German Foreign Ministry.
Dialogue was "very important" to avoid the risks of escalation, including "misunderstandings and an accident," the ministry added.
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Major powers obligated to aid Iran
Iran's state news agency, Irna, quoted Iranian Deputy Foreign Minister Abbas Araghchi as telling Plötner that Germany and the other 2015 treaty partners were obligated to uphold the deal, despite the unilateral exit announced last year by US President Donald Trump.
The 2015 deal, intended to keep Iran from obtaining a nuclear weapon, promised economic incentives in exchange for limits on Tehran's nuclear activities.
Citing an alleged threat from Iran, the United States has sent an aircraft carrier to the Persian Gulf and increased the number of troops in the region by 1,500.
ipj/sms (AP, dpa, AFP, Reuters)