US Secretary of State Antony Blinken and the head of the UN nuclear watchdog, Rafael Grossi, discussed Iran’s nuclear program during a meeting in Vienna on Friday.

According to a readout of the meeting by the US State Department, they discussed nuclear safety, security, and safeguards issues, including “outstanding verification issues in Iran.”

The International Atomic Energy Agency has regularly stressed the need for Iran to provide technically credible explanations for the presence of uranium particles of anthropogenic origin at Varamin and Turquzabad and to inform the Agency of the current location(s) of the nuclear material and/or of contaminated equipment.

“These outstanding safeguards issues stem from Iran’s obligations under its Comprehensive Safeguards Agreement and need to be resolved for the Agency to be in a position to provide assurance that Iran’s nuclear program is exclusively peaceful,” Grossi said last year.

Last week, Grossi said, “The Agency has lost continuity of knowledge in relation to [Iran’s] production and inventory of centrifuges, rotors and bellows, heavy water and uranium ore concentrate.”

Iran has enough uranium enriched to up to 60% for three atom bombs and is still stonewalling the agency on key issues, IAEA reports showed in November 2023. Iran's stock of uranium enriched to up to 60% grew by 6.7 kg (14.8 pounds) to 128.3 kg (282.9 pounds) since the last report on September 4, one of the two reports to member states seen by Reuters said. That is more than three times the roughly 42 kg (92.6 pounds) that by the IAEA's definition is theoretically enough, if enriched further, for a nuclear bomb. Weapons-grade is around 90% purity.

Earlier in March, France, Germany and the UK (E3) warned that Iran has "pushed its nuclear activities to new heights" in spite of global sanctions. The trio said that over the past five years, the levels of the country's enrichment “are unprecedented for a state without a nuclear weapons program". The observations were made to the IAEA Board of Governors on March 7.

In September 2023, Tehran withdrew the designation of several inspectors assigned to conduct verification activities in Iran under the Non-Proliferation Treaty Safeguards Agreement.

In December, Ali-Akbar Salehi, the former head of Iran's nuclear agency, implied that Iran has everything it needs for an A-bomb.