Iran’s Bushehr nuclear power plant was struck by a projectile Tuesday evening, the United Nations atomic energy agency confirmed Wednesday, in an incident that has raised immediate concerns about the risk of a nuclear accident as US and Israeli strikes continue across the country.

The International Atomic Energy Agency said it had received a report from Iran confirming that a projectile hit the premises of the Bushehr complex. The plant reported no damage to its facilities and no injuries to staff, according to the IAEA statement — but the agency’s carefully chosen language did little to conceal the gravity of what it was disclosing. Any strike on an active nuclear facility, however limited in immediate consequence, crosses a threshold that the international community has long regarded as categorically dangerous.

IAEA Director General Rafael Mariano Grossi used the confirmation to renew what has become an increasingly urgent appeal. He reiterated his “call for maximum restraint during the conflict to prevent risk of a nuclear accident” — language that reflects growing alarm within the agency about the trajectory of a war being fought in a country with significant nuclear infrastructure.

Read also: Top Iran Security Chief, Ali Larijani Eliminated By Israeli Strike

The US military’s Central Command, which oversees American airstrikes across southern Iran, did not immediately respond to a request for comment on whether US forces were responsible for the strike on Bushehr. Israel had also not commented at the time of the agency’s statement.

The IAEA’s disclosure marks the first official confirmation of the Bushehr incident from any party outside Iran or Russia, which jointly operates the plant. That the watchdog agency felt compelled to issue a formal public statement — rather than handle the matter through quieter diplomatic channels — signals the seriousness with which Grossi and his staff are treating the development.

Bushehr, located on Iran’s southwestern coast along the Persian Gulf, is the country’s only operational nuclear power plant. It generates electricity for the national grid and has been a point of international scrutiny for decades, though it has been subject to IAEA safeguards and monitoring since it came online. Unlike Iran’s uranium enrichment facilities at Natanz and Fordow — which have been primary targets in previous Israeli and American strike planning — Bushehr is a civilian power generation facility. Its reactor operates with Russian-supplied fuel under arrangements that have kept it within the bounds of international non-proliferation frameworks.

Read more: Italy Attack: Iran Warns Countries To Keep Out Of War

That distinction matters enormously in terms of nuclear risk. A strike on an operating reactor, even one that causes no immediate structural damage, raises the spectre of scenarios that nuclear safety experts have long identified as among the most catastrophic imaginable. Reactor cooling systems, fuel storage pools, and containment structures are all vulnerable to the kind of collateral damage that a near-miss or even a relatively minor direct hit could cause. The consequences of a cooling failure or containment breach at an operating reactor would not respect the boundaries of the conflict — radioactive contamination from a Bushehr incident would threaten not only Iran but the entire Persian Gulf region, including the oil infrastructure of Saudi Arabia, Kuwait, the UAE and other states that have so far remained outside the direct fighting.

The 1986 Chernobyl disaster and the 2011 Fukushima accident — both caused by failures in peacetime, without the additional variables of active military strikes — remain the reference points for what a major nuclear plant accident can mean. Neither involved a facility under attack. Bushehr now does.

Grossi has been sounding warnings about nuclear safety in Iran since the conflict began, and Tuesday’s incident gives those warnings a new and concrete urgency. The IAEA’s ability to monitor Iran’s nuclear sites has already been complicated by the war; inspectors’ access and communications with Iranian counterparts have been disrupted by the broader breakdown in civilian infrastructure that comes with sustained bombardment.

The geopolitical dimensions of the Bushehr strike — if confirmed as deliberate rather than incidental — extend well beyond Iran. Russia built the plant and has a formal partnership with Tehran on its operation. Moscow has maintained an ambiguous posture toward the US-Israeli war, neither openly condemning the strikes nor supporting them, while reportedly serving as a diplomatic back-channel in some contexts. A strike on a Russian-constructed and partly Russian-operated facility introduces a new variable into that calculation, and Russian officials had not publicly responded to the Bushehr incident by the time the IAEA issued its statement.

The absence of claimed responsibility, combined with Central Command’s silence, leaves the question of who struck Bushehr formally unresolved. In the context of a conflict in which both the United States and Israel have conducted extensive strikes across Iran, and in which Iranian air defences have also been firing missiles that sometimes miss their intended targets, the source of the projectile remains officially undetermined.

What is no longer undetermined is that a nuclear power plant in an active war zone has been hit. The IAEA said the damage was minimal. Whether that holds, and whether further strikes approach the facility again, is now one of the most consequential open questions of the war.