The U.S. and its allies Britain, France and Germany are pushing other countries on the U.N. nuclear watchdog’s board to pass a resolution next week reporting Iran to the U.N. Security Council for the first time in 20 years, diplomats said on Friday.

If passed, the resolution would follow up on one adopted on June 12 of last year declaring Iran in breach of its non-proliferation obligations for not fully cooperating with an investigation into uranium traces found at undeclared sites.

Israel started bombing Iran’s nuclear facilities the next day, soon joined by the United States, destroying or badly damaging Iran’s uranium-enrichment plants.

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

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

A draft text for the resolution has yet to be formally submitted to the board and negotiations between countries over the exact wording are ongoing, diplomats said. A draft is usually formally submitted early in the week of a board meeting.

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 to 60% without making a bomb. The amount it has enriched to that level is “a matter of serious concern” to the IAEA.

The IAEA believes well over 200 kg of that highly enriched uranium has survived the bombardments and is held in a tunnel complex at Isfahan and at the Natanz facility.

(Reporting by Francois Murphy and John Irish; Editing by Alison Williams and Kevin Liffey)