The International Atomic Energy Agency (IAEA) confirmed that it has discovered traces of uranium enriched to 83.7% in Iran, barely under the 90% minimum needed to produce a nuclear bomb.

"Discussions are still ongoing" to determine the origin of these particles, the International Atomic Energy Agency (IAEA) said in a report seen by AFP.

Asked about the particles found in Iran, the government in Tehran said "unintended fluctuations" during the enrichment process "may have occurred."

In 2015, Iran reached a deal with world powers to limit the enrichment of uranium and allow IAEA inspectors to visit its nuclear sites, in return for the lifting of economic sanctions.

But the deal stalled in 2018.

Iran has been enriching uranium well over the limits laid down in the deal and the IAEA believes its estimated stockpile is more than 18 times the limit set out in that accord.

An IAEA report reavealed that during an inspection "on 22 January 2023, the agency took environmental samples... at the Fordow (sic) plant, the analytical results of which showed the presence of highly enriched uranium particles containing up to 83.7% U-235."

"These events clearly indicate the capability of the agency to detect and report in a timely manner, changes in the operation of nuclear facilities in Iran," it continued.

In the report, the United Nations' nuclear watchdog also said that Iran's estimated stockpile of enriched uranium had reached more than 18 times the limit set out in the 2015 accord between Tehran and world powers.

The IAEA estimated Iran's total enriched uranium stockpile was 3,760.8 kilograms (8,291 pounds) as of Feb. 12, an increase of 87.1 kilograms compared to the last report in November.

The limit in the 2015 Iran nuclear deal was set at 202.8 kilograms of uranium.

The IAEA has also repeatedly warned it has lost its ability to fully monitor Iran's program since the country started to restrict its access in February 2021.

Iran's stockpile of uranium enriched to 60% is now at 87.5 kilograms, up from 62.3 kilograms, the report said.

Iran currently also has 434.7 kilograms of uranium enriched up to 20%, up from 386.4 kilograms in the November report.

Tehran has always stressed that it is only interested in peaceful nuclear technology.

In 2015, Iran pledged to limit its nuclear program, which led to Western sanctions being lifted in return. The pact was intended to prevent the construction of nuclear weapons by Tehran.

After the U.S. unilaterally pulled out of the agreement in 2018 under then-president Donald Trump, Tehran responded by expanding its uranium enrichment and limiting IAEA inspections.

Negotiations to revive the nuclear agreement, in which Germany is also involved, have been stalled for months.