© Screengrab IRIB/APThree versions of domestically built centrifuges used in enrichment process.
Iran's state-run IRNA news agency earlier the same day quoted Foreign Minister Mohammad Javad Zarif as confirming that the 300-kilogram limit had been breached. The comment came after the semiofficial Fars news agency quoted a source as saying that IAEA inspectors had measured the stockpile and confirmed it had surpassed the cap.
The UN watchdog is expected next to file a report on the issue.
The terms of the accord limit the enrichment and stockpiles of Iran's uranium, and reduce the country's nuclear capabilities in return for relief from international sanctions. But the United States unilaterally abandoned the pact in May 2018 and later reimposed sanctions on Iran that had been lifted under the deal.
Iranian officials have complained that the remaining parties to the deal -- Britain, France, Germany, China, and Russia -- had failed to mitigate the effects on the country's economy of the U.S. sanctions, and announced that Tehran was on track to pass the low-enriched-uranium limit set under its pact.
IRNA quoted Foreign Minister Zarif as saying that "if Europeans do what they have to do, our measures are reversable."
President Hassan Rohani has said that Iran might start enriching uranium beyond the 3.67 percent concentration limit set by the nuclear deal if the five countries failed to meet their commitment.
European countries have warned that any violation of the agreement, which aimed at heading off any pathway to developing a nuclear bomb, would bring consequences. Enriched uranium is used to make reactor fuel and potentially nuclear weapons.
Relations between Washington and Tehran have plummeted since the U.S. pullout of the nuclear deal, with recent attacks on oil tankers in the Gulf of Oman and near the Strait of Hormuz exacerbating the situation.
Washington has blamed Iran for the incidents, while Tehran denied any involvement.
In a speech on July 1, Iranian Foreign Minister Zarif said that Iran "will never yield to pressure from the United States. Today, Iran has to stand against U.S. economic sanctions through domestic production and relying on national potentials," Zarif said, without mentioning the country's nuclear program.
In announcing the U.S. withdrawal from the Iran accord, President Donald Trump argued that the terms were not tough enough to prevent Iran from developing nuclear weapons and did not address the country's missile program or its support for militants in the region.
Iran has denied it supports insurgent activity and said its nuclear program is strictly for civilian energy purposes.
Russian Deputy Foreign Minister Sergei Ryabkov on July 1 said it was "regrettable" that the 300-kilogram limit had been exceeded, but said the development should not be overdramatized, according to the state-run news agency TASS.
Interfax quoted Ryabkov as saying the breach did not come as a surprise, and urged Iran to take a responsible approach toward implementing the safeguards agreement with the IAEA under the nuclear deal.
Comment: See also: