VIENNA/PARIS — The United States, Britain, France and Germany are seeking a resolution by the U.N. nuclear watchdog's board next week that would report Iran to the U.N. Security Council for the first time in 20 years, according to diplomats and the proposed text seen by Reuters.

If passed, the resolution would follow up on one adopted on June 12 of last year, which declared Iran in breach of its non-proliferation obligations for failing to fully cooperate with an investigation into uranium traces found at undeclared sites.

Israel began bombing Iran's nuclear facilities the following day, soon joined by the United States. Iran's uranium-enrichment plants were destroyed or badly damaged in the campaign.

Since then, Iran has not allowed International Atomic Energy Agency (IAEA) inspectors to return to the bombed sites or to verify what remains of its stocks of enriched uranium, some of which was enriched to up to 60 percent purity — a short step from weapons grade.

Fresh diplomatic escalation

A resolution by the IAEA's 35-nation board reporting Iran to the Security Council would also mark the culmination of a standoff over IAEA access to those sites. Over the past year, the board has passed two resolutions demanding that Iran declare its enriched uranium stocks and grant the agency full access to verify them.

"(The board) requests the (IAEA) Director General to transmit this resolution and the previously adopted resolutions ... to all Members of the Agency and to the Security Council and the General Assembly of the United Nations," the latest resolution draft seen by Reuters states.

The draft also "reiterates its call upon Iran to urgently remedy its non-compliance with its Safeguards Agreement by taking all steps deemed necessary by the Agency and the Board, so that the Director General can provide the necessary assurances regarding the correctness and completeness of Iran's declarations."

The draft has not yet been formally submitted to the board, and diplomats said negotiations over the exact wording are ongoing. Whenever the four powers have submitted a draft resolution on Iran in recent years, it has passed.

Concrete action by the Security Council against Iran is considered unlikely, however, since Tehran's allies Russia and China are permanent, veto-wielding members of the council.

Even so, referral to the council carries political weight. It was the council that imposed the U.N. sanctions on Iran over its nuclear program, most of which were lifted under the 2015 nuclear deal between Iran and major powers. That accord, which capped Iran's enrichment at 3.67 percent in exchange for sanctions relief, has been in disarray since the United States withdrew from it in 2018 and Iran subsequently enriched far beyond its limits.

IAEA concerns over enrichment

Iran has often retaliated after IAEA board resolutions against it by escalating its nuclear activities or scaling back cooperation with the agency, but its options for both are currently extremely limited. It remains unclear what other repercussions the move might have on Tehran's conflict with the United States.

As a party to the nuclear Non-Proliferation Treaty (NPT), Iran has the right to develop nuclear technology, including enrichment, for peaceful purposes. Iran says it would never produce nuclear weapons. It is, however, the only country to enrich uranium to 60 percent without making a bomb, and the IAEA has said the amount it has enriched to that level is of serious concern.

The IAEA estimates that Iran held 440.9 kg of uranium enriched to that level before its sites were bombed. According to an IAEA yardstick, that quantity would be enough, if enriched further, for 10 nuclear weapons.