Britain, France and Germany late on Monday submitted a resolution to the U.N. nuclear watchdog's board, censuring Iran over its lack of cooperation with the agency despite U.S. opposition, two diplomats said.

It was the latest of numerous diplomatic maneuvers by Western powers who fear Iran might be seeking to develop a nuclear weapon — a claim the Islamic Republic denies.

"The text has been formally tabled," one diplomatic source told AFP, with a second confirming the information.

The move to submit a motion against Iran was driven by an "urgency to react to the gravity of the situation," diplomats told AFP earlier.

The International Atomic Energy Agency (IAEA) says Iran is the only non-nuclear weapon state to enrich uranium to the high level of 60%, while it keeps accumulating large uranium stockpiles.

Uranium enriched to 60% is close to the levels of 90% needed for atomic weapons and well above the 3.67% used for nuclear power stations.

The board of governors passed the last such resolution criticizing Iran in November 2022, prompting Tehran to retaliate by stepping up its uranium enrichment activities.

At the opening of the meeting on Monday, IAEA head Rafael Grossi reiterated his concerns, saying: "It's unacceptable to talk about nuclear weapons, as some people do in Iran."

Referring to the limited oversight the agency now has on Tehran's nuclear program, Grossi warned that the current "knowledge gap ... is making it very difficult to go back to diplomacy."

At the last board meeting in March, European powers shelved their plans to confront Iran due to a lack of support from Washington.

The United States denies it is hampering European efforts to hold Tehran accountable but fears a censure could aggravate Middle East tensions ahead of U.S. presidential elections in November, diplomats say.

'Essential and urgent'

Cooperation between Iran and the IAEA has severely deteriorated in recent years, with the U.N. nuclear watchdog struggling for assurances that Iran's nuclear program is peaceful.

Diplomats say maintaining the current policy of inaction amid Iran's escalation is no longer tenable and the U.S. position could change ahead of the IAEA vote scheduled for later this week.

In May, Grossi visited Iran in a bid to improve cooperation, calling for "concrete results ... soon."

In the meantime, the death of Iran's President Ebrahim Raisi in a helicopter crash last month has put negotiations on hold, with diplomats suggesting Tehran was using the accident as an excuse to stall.

Grossi, however, rejected that claim Monday, saying the pause was "not part of any delaying tactic" by Iran.

He added he was ready to "sit down with the new authorities" after Iran's presidential election on June 28.

The draft resolution obtained by AFP says it is "essential and urgent" that Tehran provides "technically credible explanations" for the presence of uranium particles found at two undeclared locations in Iran.

Furthermore, Iran has to "reverse its withdrawal of the designations of several experienced Agency inspectors," and "without delay" reconnect the cameras used to monitor nuclear activities.

The draft also notes the "concerns" surrounding "recent public statements made in Iran ... regarding its technical capabilities to produce nuclear weapons and possible changes to Iran's nuclear doctrine."

'Serious and effective response'

Iran has gradually broken away from its commitments under the nuclear deal it struck with world powers in 2015.

The landmark deal provided Iran sanctions relief in exchange for curbs on its atomic program.

But it fell apart after the unilateral withdrawal of the United States under then-president Donald Trump in 2018.

Efforts to revive the deal have failed.

"A showdown at the board reflects a wider impasse over Iran, with little diplomatic activity but increasing concern over a program that continues to expand in scale under limited international oversight," Naysan Rafati, an Iran analyst at the Crisis Group, told AFP.

Ali Shamkhani, a political adviser to Iran's Supreme Leader Ali Khamenei, warned Saturday on X that if "some misguided European countries ... adopt a hostile stance towards Iran ... at the board, they will face a serious and effective response from our country."

Mikhail Ulyanov, Russia's ambassador to the international organization in Vienna, wrote on X on Sunday that tabling an "anti-Iranian resolution" could risk "seriously deteriorating the situation."