International Atomic Energy Agency (IAEA) Director General Rafael Mariano Grossi warned that the nuclear non-proliferation regime that has underpinned international security for more than half a century “is on the line.”

“The dramatic events in Iran have become even more serious with last night’s bombardments and the potential widening of the conflict,” Grossi said while addressing an emergency session of the UN Security Council on Sunday after the US strikes on Iranian nuclear sites.

“We have a window of opportunity to return to dialogue and diplomacy,” he said, adding: “If that window closes, violence and destruction could reach unthinkable levels and the global non-proliferation regime as we know it could crumble and fall.”

“We must return to the negotiating table and allow the IAEA inspectors, the guardians of the NPT, to go back to Iran’s nuclear sites and account for the stockpiles of uranium, including, most importantly, the 400kg enriched to 60%,” he added.

US President Donald Trump said Sunday that American forces bombed Iran’s Fordo, Natanz and Isfahan nuclear sites.

The attacks came in the latest escalation in a US-backed Israeli military assault on Iran since June 13 that prompted Tehran to launch retaliatory attacks on Israel.