WASHINGTON — The U.S. is increasing diplomatic pressure on Iran by proposing that Tehran be referred to the United Nations Security Council over its stonewalling of nuclear inspectors, who have been unable to verify the location of the country’s stockpile of near-weapons-grade uranium.

The maneuver is expected to unfold at the International Atomic Energy Agency’s board of governors meeting in Vienna, which began on Monday. Iran has blocked the U.N. watchdog from reviewing Iran’s uranium inventory for 15 months, since the start of Israeli airstrikes in June 2025.

The U.S. resolution demands that Iran “urgently remedy its non-compliance” and allow checks to ensure “the non-diversion of nuclear material,” according to a copy of the two-page document seen by Bloomberg News.

The IAEA has grown increasingly frustrated over Iran’s obstruction of its inspectors’ work.

“There’s no engagement, there is no information, and we are being told that they are not going to cooperate until there is some agreement in the wider political negotiation,” IAEA Director General Rafael Mariano Grossi said at a press briefing on Monday.

The last time Washington referred Iran’s atomic file to the U.N., Israel started strikes against the nation’s nuclear facilities within 24 hours, triggering a 12-day war. The start of the current conflict on Feb. 28 came a day after the IAEA reported the observation of renewed activity near bombed sites.

U.S. President Donald Trump has repeatedly said the ongoing military campaign is aimed at preventing Iran developing a nuclear weapon. The conflict is mired in stalemate, with less known about Iran’s nuclear capabilities than before the mid-2025 attacks.

Trump said last week the U.S. is contemplating fresh strikes against deeply-buried nuclear facilities.

“We may hit Pickaxe very soon,” Trump told reporters on Sept. 4, referring to a heavily fortified mountain site just south of Iran’s main uranium enrichment facility in Natanz.

“We know everybody that’s moving at Pickaxe,” Trump said. “If anything goes bad we hit them.”

Iran said calls to resume inspections are “meaningless” amid ongoing military strikes because the situation on the ground remains too hazardous.

The IAEA “must first call on aggressors -– the U.S. and Israeli regime — to stop attacking or threatening to attack safeguarded peaceful nuclear facilities,” Iran’s permanent mission to the U.N. posted on X. “Iran has every right to protect its national interests on its own.”

The IAEA hasn’t been able verify Iranian activities at the site, located in the Zagros Mountains 220 km (140 miles) south of Tehran. Inspectors have also been blocked from returning to damaged plants in Fordow, Isfahan and Natanz, where Iran’s 440.9 kilograms (972 pounds) and 8,599.6 kilograms of lower enriched material was last seen.

“The agency’s lack of information about this nuclear material and access to facilities to verify it is a matter of proliferation concern,” Grossi reported to diplomats last week, adding that Iran needs to allow inspectors back in “with the utmost urgency.”

While historically a Security Council referral could result in economic sanctions, or the authorization of military force, China and Russia are unlikely to support new action against Tehran. They’ve repeatedly criticized Washington’s campaign and contested the legality of U.N. sanctions snapped back on Iran last year.

The IAEA’s board of governors convenes for its weeklong meeting over Iran and other regional issues on Monday. It’s the first for new U.S. Ambassador Preston Wells Griffith III, a White House special assistant during Trump’s first term.

—With assistance from Eltaf Najafizada.

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