The confidential report sent to IAEA member states reportedly states that Iran's stock of low-enriched uranium as of August 21 was 88.4 kg (194.89 pounds), below the 202.8-kg limit, and that the level of enrichment did not exceed a 3.67 percent cap.
The report is the third by the International Atomic Energy Agency (IAEA) since the January inauguration of US President Donald Trump, who has called the agreement made under his predecessor Barack Obama, "the worst deal ever negotiated."
In April, he ordered a review of whether a suspension of nuclear sanctions on Iran was in the US interest.
Under US law, the State Department must notify Congress every 90 days of Iran's compliance with the deal. The next deadline is October and Trump has said he thinks by then the US will declare Iran to be non-compliant.
Under the accord, Iran could not get sanctions relief until the IAEA was satisfied Tehran had answered outstanding questions about the so-called "possible military dimensions" of its past nuclear research.
Uranium enriched to a grade of under 5 percent of purity is considered suitable for civilian nuclear energy, while weapons-grade uranium requires enrichment of around 90 percent. Certain types of plutonium are a prime ingredient of atomic bombs.
Iran's stock of so-called heavy water - a moderator used in a type of reactor that can produce plutonium - stood at 111 tonnes, below the 130-tonne limit agreed in the deal, the report said, adding that Iran had restarted production of heavy water on June 17 after a maintenance shut-down of the plant on April 27.
Iran has breached its heavy water limit slightly on two occasions before quickly shipping some amounts to Oman to get below the threshold.
Tehran rejects inspectors' visit
Iran this week also dismissed the idea of inspectors visiting its military bases following a report that the US ambassador to the UN, Nikki Haley, had recently called on the IAEA to seek access to Iranian military bases.
She reportedly said this would help ensure Iran was not concealing activities banned under the 2015 deal.
"Iran's military sites are off limits," Iranian government spokesman Mohammad Baqer Nobakht said.
"All information about these sites are classified. Iran will never allow such visits. Don't pay attention to such remarks that are only a dream."
Iranian President Hassan Rouhani later said the US call was unlikely to be accepted by the IAEA.
On Wednesday France suggested the 2015 nuclear deal could be supplemented through "future consultations" to include the post-2025 period and tackle Iran's development of ballistic missiles.
The US, UK, France and Germany have complained several times to the UN about Iran's tests of ballistic missiles, which they contend are in defiance of a 2015 UN resolution enshrining the nuclear deal.
jbh/kms (Reuters, AFP)