According to a U.N. watchdog and an Iranian media report, Iran has converted a small amount of its highly enriched uranium stockpile into material that can detect cancers.

Iran’s decision that it will convert uranium means that the material can be further refined to weapons-grade levels. This development occurs as negotiations in Vienna about restoring Tehran’s nuclear agreement with world powers are in flux.

Negotiators had previously stated that they had completed a long-running effort to bring Iran and the United States back into the accord , just as a Russian demand put the talks in a chaotic pause.

The United Kingdom and Iran have agreed to release prisoners. News of Tehran’s decision to reprocess uranium seems to indicate that negotiations could still take place in Vienna, with the parties possibly reaching a deal. Israel, Iran’s archrival, has been criticizing efforts to revive the agreement.

The International Atomic Energy Agency stated Friday that Iran had used 2.1 kg (4.6 pounds) its 60% enriched Uranium to produce “highly enriched targets” at an Isfahan facility. The IAEA stated that those “targets” would be irradiated at Tehran Research Reactor, and then used later to make molybdenum 99.

Molybdenum 99 is converted into technetium-99m within days. This is an isotope that is used to scan the body for cancer detection and blood supply. According to the Energy Department, more than 40,000 medical procedures are performed every day in the United States using technetium-99m.

To avoid the proliferation risk of highly enriched uranium, many countries are using low-enriched Uranium more frequently.

Iran’s semi-official Mehr news agency said that some of the material had been reprocessed, citing unnamed officials. According to the report, 2 kilograms (4.41 lbs) of this material could be used to help 1 million people. According to the IAEA, Iran’s stockpile was 33.2 kilograms (73.19 lbs) of 60% enriched Uranium as of February 19, which is a technical step away from 90% weapons-grade level.

Mehr reported that “the materials converted to a ‘target’ were irradiated and has no risk of spreading and Western countries can’t criticize Iran over it.”

Iran committed to limiting its enrichment to 3.67% and ending the use of advanced centrifuges. A stockpile of 300 kg (661 pounds) was also agreed under the 2015 agreement.

Iran’s stockpile was 2,883 kilograms (6.355 pounds) as of February 19, with more advanced centrifuges spinning. Although Iran has long maintained that its nuclear program is peaceful, both the West and IAEA claim that Tehran had an organised military nuclear program. It was ended in 2003.

The use of 60% enriched Uranium to make isotope material does not mean that it can be reconstituted for a larger stockpile. This is stated by Daryl G. Kimball (executive director, Washington-based Arms Control Association).

He stressed however that Iran’s stockpile must be shipped again to get back to 2015 levels.

Kimball said that Iran may be trying to show that they have better intentions at this crucial juncture of the negotiations, which is the eleventh hour. “This could be an attempt to show they are interested in a deal.”

He said that it could also be ex post facto a reason to enrich uranium up to 60%. This could be a cover story to justify what they have done and didn’t do.

On Friday, Israel’s Prime Minister Naftali Bennet and Foreign Minister Yair Lepid issued a joint statement warning the U.S. not to lift a terrorist designation on Iran’s paramilitary Revolutionary Guard. This is a final demand from Iran and , which was the subject of the final negotiations at Vienna.

The Israeli statement, which used an acronym for the Guard, stated that “The attempt to delist IRGC as a terror organization is an insult and to the victims” “We are unable to believe that the IRGC will be delisted as a terrorist organisation in return for a promise to not harm Americans,” said Israel.