The United Nations atomic watchdog said on Thursday it has observed construction activity at Iran’s Pickaxe Mountain, a heavily-fortified site suspected of housing nuclear-related activities.
International Atomic Energy Agency chief Rafael Grossi said new movement at the complex had been spotted in remote imagery.
“There are some indications that there is movement around this construction site,” Grossi told Bloomberg Television.
“We don’t have any concrete information as to activities that may be taking place there,” he added.
Pickaxe Mountain, located in the Zagros Mountains roughly 220 kilometers south of Tehran, began drawing particular attention after an Iranian centrifuge workshop was sabotaged six years ago.
Iran said it intended to move sensitive nuclear-related infrastructure underground to protect it from attack.
“They said at the time, ‘we are going to put everything in tunnels, inside a mountain,’” Grossi told Bloomberg. “This was going to be impermeable and protected from attacks.”
Western intelligence suspects Iran is building an undeclared enrichment facility inside Pickaxe Mountain that could be used to enrich uranium.
On Wednesday, US President Donald Trump mentioned the Pickaxe at a Republican rally and said: “We notice there’s a little activity at Pickaxe. I would advise Iran not to get cute because we will have to hit them very hard.”
Trump has been threatening strikes on Pickaxe Mountain since at least mid-July.
Unverified nuclear stockpile
At the quarterly meeting of the IAEA board of governors in Vienna this week, Grossi said the UN watchdog has been completely blind regarding Iran's nuclear program since at least June 2025, when the US and Israel launched a 12-day conflict that included strikes on nuclear sites.
Prior to the June strikes, the IAEA calculated that Iran possessed approximately 440,9 kilograms of uranium enriched to 60%, which is close to the 90% needed to make a bomb and well above the 3.67% limit set by a 2015 now-defunct agreement with Iran.
On Wednesday, the UN atomic watchdog’s board reported Iran to the UN Security Council for the first time in 20 years, citing it for failure to cooperate in a long-running investigation into uranium traces detected by inspectors at undeclared sites.
The resolution accused Iran of failing to comply with its nuclear reporting obligations, citing it for failure to cooperate in a long-running investigation into uranium traces detected by inspectors at undeclared sites.
Tehran responds
In return, Iranian deputy Foreign Minister Kazem Gharibabadi slammed the IAEA for referring Iran's nuclear file to the UN Security Council.
Gharibabadi wrote in a post on X, “They attack Iran's safeguarded nuclear facilities, disrupt the normal process of verification, and then use that very disruption as a pretext to issue a resolution.”
He described the approach as “fabricated”, saying: “With these fabrications, you cannot make up for the failure of your policies and actions, nor achieve any result at the Security Council.”
Iran’s mission to the UN also denounced the resolution. “It follows a telling trend and facilitates further erosion and ultimate collapse of the proliferation regime as a whole,” the mission said in a post on X.
The resolution sparked criticism in Tehran. Politicians said Iran should accelerate the development of the nuclear program and reconsider its membership in the Nuclear Non-Proliferation Treaty.
Iranian deputy Rouhollah Najabat said that following the IAEA Board of Governors’ resolution, Tehran will accelerate the technical development of its nuclear program.
“Westerners should know that the path of threats and referring the case to the Security Council is ineffective,” Najabat said.
He added that Iran will make no concessions but will take a “more serious and firm” approach.
The deputy warned that the Iranian parliament will not remain “passive.”
Lawmaker Alireza Salimi, a member of parliament’s presiding board, said Iran had “serious options” for responding. “One of our options could be withdrawal from the NPT,” he said, adding: “Iran will certainly respond.”
