The head of the UN nuclear watchdog, Rafael Grossi, arrived in Tehran on Monday with the objective of repairing strained relations and bolstering cooperation and transparency between the agency and Iran.

“I proposed a set of concrete practical measures for the revitalization of the 4 March 2023 Joint Statement with aim of restoring process of confidence building and increasing transparency,” the IAEA Chief tweeted after a meeting with Iran’s Foreign Minister Hossein Amir-Abdollahian.

The IAEA delegation’s visit comes at a time the agency has admitted to having lost crucial "continuity of knowledge" regarding Tehran’s nuclear activities.

Before his departure, Grossi highlighted the increased accumulation of enriched uranium by Iran, a matter that raises alarms about potential weaponization.

The country is said to be enriching uranium to up to 60% purity, close to the 90% of weapons grade, and has enough uranium enriched to that level to make “several” nuclear bombs if it chose to do so.

Those concerns, underscored by Grossi’s own admission that the IAEA cannot fully ensure that Iran does not have additional, undisclosed centrifuges, potentially hidden from the agency's oversight.

Atomic Energy Organization of Iran chief Mohammad Eslami, meanwhile, voiced his hope that despite the media’s “negative” portrayal of Iran’s nuclear program, the IAEA can fulfill its role as an international entity independently, free from political influence and pressure.

Following Grossi’s last visit to Iran in 2023, the two parties issued a joint statement, among which Tehran had promised to continue its cooperation and provide further information and access to address outstanding safeguards issues related to three specific locations. Additionally, Tehran had agreed to allow the IAEA to implement additional verification and monitoring activities on a voluntary basis.

Since then, Iran has reneged on its promises and has deactivated surveillance devices, barred senior inspectors, and refused to disclose new nuclear facilities.

While international concerns about Iran’s nuclear program have continued to mount, Iran has often avoided being censured by the IAEA board for its non-compliance.

Grossi is also likely to attend an Iranian nuclear conference while on his two-day tour in Iran – sparking criticism.

“Such a visit risks legitimizing Tehran’s development of nuclear technology outside IAEA safeguards and Iran’s provocative nuclear advances, while minimizing the regime’s non-compliance with its nonproliferation obligations," nuclear expert Andrea Stricker said.