NEW YORK — Iran has breached a crucial limit on the level of uranium enrichment set out in the 2015 nuclear deal, the country’s atomic energy agency said Monday, as China, another signatory to the deal, accused the United States of “bullying” Tehran with crippling economic sanctions.

Behrouz Kamalvandi, a spokesman for Iran’s atomic energy agency, told the Iranian state broadcaster IRIB that the country had surpassed a limit of 3.67 percent uranium enrichment and was prepared to go higher.

Kamalvandi later told another Iranian news outlet, ISNA, that the enrichment level was above 4.5 percent.

Fredrik Dahl, a spokesman for the International Atomic Energy Agency, the organization tasked with monitoring Iran’s compliance with the limits set out in the deal, confirmed that Iran is enriching uranium above 3.67 percent but did not specify to what level.


The change moves Iran closer to — but still far short of — the level of uranium enrichment needed to produce nuclear weapons. But Iran has maintained that the higher enrichment level would be for peaceful purposes only.

The United States withdrew last year from the landmark nuclear accord with other powers and Iran, and this May imposed new punishing economic sanctions on Iran.

Iran has responded with a series of steps away from its obligations under the accord, which was intended to block Tehran from obtaining a nuclear weapon, in exchange for the lifting of sanctions.

The United States and Iran have teetered on the brink of armed conflict in recent weeks, with both sides issuing bellicose warnings. Six tankers were attacked in May and June near the Strait of Hormuz, a critical passageway for oil shipments, and the United States has blamed Iran. The downing of a US surveillance drone by Iran last month further ratcheted up tensions and nearly resulted in a military strike by the United States.


A spokesman for the Chinese Foreign Ministry, Geng Shuang, criticized the United States in a news conference Monday.

“The US side not only unilaterally withdrew from the agreement but also created more and more obstacles for Iran and other parties to implement the agreement through unilateral sanctions and long-armed jurisdiction,” he said. “It has been proven that unilateral bullying has become a worsening ‘tumor’ and is creating more problems and greater crises on a global scale.”

China has called the United States’ actions the root cause of the issues with Iran before, and officials have long spoken critically of US sanctions on Iran. But the blunt language Geng used was a stronger declaration of blame.

European signatories to the nuclear agreement have found themselves in a difficult position, stuck between adhering to the US sanctions that target Iran’s oil industry and obligations to ease the economic burden on Iran under the nuclear deal.

Monday’s announcement came one day after Iran’s government spokesman, Ali Rabiei, said the country was just hours away from breaching the 3.67 percent limit on uranium enrichment. A week earlier, Iran announced it had exceeded another critical limit on how much nuclear fuel it could stockpile under the agreement.

Tehran has said that reducing its commitments under the deal is not a direct violation of the terms of the nuclear agreement, saying it is exercising its right to react to the United States’ walking away from the accord.

After the Trump administration announced its sanctions in May, Iran set a two-month deadline for the European signatories to come up with a strategy to ease the economic impact. Iran began to surpass the enrichment limits Sunday because the Europeans had not provided any help, and Tehran set another 60-day deadline before it will take further steps beyond the limits in the 2015 deal.


Less than 1 percent of naturally occurring uranium is U-235, a highly radioactive isotope, and enrichment means increasing that level. The 2015 agreement limited Iran to producing uranium that is no more than 3.67 percent U-235, a typical level of enrichment for use in a nuclear power plant.

Before the pact was signed, Iran had raised some of its uranium stockpile to 20 percent, which it said was needed for a research reactor. Atomic bombs use much more highly enriched uranium, generally over 80 percent.

Despite the increase in its uranium stockpile and its production of more highly enriched uranium, experts say Iran is still far from producing a nuclear weapon.