The US and Israel celebrated their June attacks on Iran’s nuclear installations as having degraded the country’s nuclear programme ‘by up to two years’. But verifying that claim is difficult, and the whereabouts of Iran’s nuclear materials remains uncertain. Indeed, other intelligence assessments have been less than optimistic about the strikes’ effectiveness. IAEA inspectors have not been able to access any of Iran’s nuclear facilities since the start of the war on 13 June, so there is no independent assessment available.
Cutting access to the IAEA
Following the June attack, Iran passed a bill that barred IAEA inspectors from accessing its nuclear facilities. Access had already been progressively restricted since 2018, when the first administration of President Donald Trump pulled out of the Joint Comprehensive Plan of Action. The IAEA admitted in a report in May 2025 it no longer had continuity of knowledge of the state of Iran’s nuclear programme.
The barring of the IAEA created a significant challenge for the international community. It meant that there would be no more independent verification of Iran’s compliance with its safeguards agreement under the Non-Proliferation Treaty (NPT). It also meant that any diplomatic engagement on Iran’s nuclear programme would rely on countries’ own intelligence estimates. That invariably creates a barrier to engagement, as there are no commonly agreed facts from which a negotiation could start.
In early September, the IAEA and Iran reached an agreement in principle that inspectors could return to conduct on-site inspections. This would include inspecting Iran’s stocks of highly enriched uranium, as well as all nuclear sites and facilities, including those damaged by the US-Israeli attacks in June. And it would allow the IAEA to conclude an independent assessment of the state of Iran’s nuclear programme, which would form an important contribution to transparency.
However, there is no agreement on when inspectors will return, or when Iran will once again provide data on its nuclear facilities to the IAEA. That makes the agreement in principle only a fragile first step towards a restored inspections regime.
The reason there is no timeline is simple: the Iranian government no longer trusts the IAEA and questions its independence as a monitoring agency. Iranian diplomats have been calling out what they perceive to be a double-standard: the IAEA was robust in condemning Russian attacks on Ukrainian nuclear power plants, Iran claims, while Israeli attacks on its nuclear facilities passed with less stringent language. (The IAEA says it condemned both in equal measure).
Iranian diplomats are pursuing a resolution at the UN to strengthen protections for civil nuclear infrastructure against attacks. In fact, this aligns with IAEA goals: Director General Rafael Grossi has promoted a plan to protect nuclear infrastructure in conflict zones since Russia began attacking the Chernobyl and Zaporizhzhia sites in Ukraine.
However, instead of working with the IAEA to further a shared goal, Iran is pushing a narrative about double standards which threatens to fuel the polarization that is hampering UN processes. Meanwhile, with no inspectors on the ground, mistrust will grow between concerned parties, and uncertainty prevails about the condition of Iran’s nuclear capabilities.
That in turn makes it much harder to reach an agreement to prevent the return of punishing sanctions on Iran, looming at the end of September.
Sanctions
The Joint Comprehensive Plan of Action (JCPoA) was successful in part because the UK, France, Germany, the US, Russia and China all worked together to make negotiations with Iran a success. This common goal does not exist anymore.
The US seems to believe its military action was sufficient to curb Iran’s nuclear programme and shows no interest in pursuing negotiations again. Iran also refuses to engage with the US since the strikes in June – a humiliation which Tehran believes makes a return to the negotiating table with Washington politically impossible. Meanwhile Russia’s relationship with Iran has changed significantly, as Western sanctions, imposed after the invasion of Ukraine, push Moscow closer to Tehran.
The UK, France and Germany have continued to negotiate with Iran – offering to delay reinstating UN sanctions if Iran restores access for IAEA nuclear inspectors, among other requirements. But the negotiating parties’ positions are far apart, and there are only days to reach an agreement before the sanctions against Iran ‘snap back’ at the end of September. On Saturday, Iran threatened to suspend cooperation with the IAEA if sanctions do snap back. Iran and the E3 are likely to continue to meet in the margins of the UN General Assembly in New York, but it is very uncertain whether an agreement can be made.
