The United States on Monday (August 16) voiced alarm over Iranian production of uranium metal reported by the United Nations nuclear watchdog as it urged the Islamic Republic to return to talks.
The State Department said the United States has seen the latest report to members by the International Atomic Energy Agency (IAEA) and contends that Iran "has no credible need to produce uranium metal".
Iran promised not to produce uranium metal, which can be used to build a nuclear bomb, as part of the 2015 Joint Comprehensive Plan of Action (JCPOA) under which it was to scale back its nuclear programme drastically in return for sanctions relief.
But Iran said earlier this year that it was researching uranium metal to provide advanced fuel for a research reactor -- one of a series of steps it took outside the JCPOA.
"On 14 August 2021, the Agency verified... that Iran had used 257g of uranium enriched up to 20% U-235 in the form of UF4 (uranium tetrafluoride) to produce 200g of uranium metal enriched up to 20% U-235," the IAEA said, according to Reuters.
Ominous Iranian progress
The IAEA added that the move was step three in a four-step plan, the fourth being the production of a reactor fuel plate.
"We have made clear that continued nuclear escalations beyond JCPOA limits are unconstructive and inconsistent with a return to mutual compliance," State Department spokesman Ned Price said.
"Iran should cease its nuclear escalations and return to negotiations toward full implementation of the JCPOA in good faith."
Nuclear talks in Vienna have been at a standstill since the inauguration of Iran's new ultraconservative president, Ebrahim Raisi, although he says he supports efforts to lift US sanctions.
World powers on July 6 warned Iran that its latest uranium enrichment efforts could imperil the nuclear talks, with the United States calling on Tehran to halt its "brinksmanship".
The cross-Atlantic condemnation came after the IAEA reported that Iran intended to enrich uranium to 20%, in the latest sign the talks could be stalling.
In May, the IAEA voiced concern that Iran had not clearly answered queries over possible undeclared nuclear activity, adding that Tehran's enriched uranium stockpile was 16 times over the allowed limit.
In April, world powers expressed "grave concern" over Iran's announcement that it would move to boost uranium enrichment up to 60%.