Iran is enriching uranium to 4.5% purity, above the 3.67% limit set by its deal with major powers, the UN nuclear watchdog policing the deal told member states in a closed-door meeting on Wednesday, diplomats familiar with the figures said.
The International Atomic Energy Agency had previously said on Monday only that Iran was over the 3.67% limit, its second breach of the 2015 deal in as many weeks. An Iranian spokesman said on Monday it had passed 4.5%, according to the semi-official news agency ISNA.
On July 1 the IAEA verified that Iran's stock of enriched uranium was 205 kg, more than the maximum 202.8 kg allowed under the agreement. At Wednesday's meeting, IAEA officials said Iran's stock of enriched uranium was now 213.5 kg.
Both figures were verified on Tuesday, the four diplomats said. Monday's enrichment level was verified using online enrichment monitors, which report in real time. They said the level reported on Wednesday, however, was the result of a sample analysis.
It was not immediately clear whether the samples tested were taken on Monday or Tuesday.
The rise in the enrichment level is still far below the 20% Iran refined to before the nuclear accord, and the roughly 90% needed to make uranium weapons-grade.
Iran says it is responding to punishing economic sanctions the United States has imposed on Tehran since Washington pulled out of the nuclear deal a year ago. Washington says it is open to talks on a more far-reaching accord but Iran says it must first be able to sell as much oil as it did before the US withdrawal.