Tensions between Iran and the UN nuclear watchdog have repeatedly flared in recent years, with relations being further strained in the wake of a 12-day war in June that saw Israeli and US strikes on key Iranian nuclear facilities.

Since the war, agency inspectors have not been granted access to key nuclear sites such as Fordo and Natanz, which were hit in the strikes in June, but they have been able to visit other sites.

In its latest confidential report, the International Atomic Energy Agency (IAEA) said it "has lost continuity of knowledge in relation to previously declared inventories of nuclear material in Iran at the affected facilities", including its stockpile of near-weapons-grade uranium.

According to the IAEA, Iran had an estimated 440.9 kilograms enriched to up to 60 percent as of June 13 but has been unable to verify it.

In theory, that stockpile is enough to produce about 10 nuclear bombs.

The agency has said Iran is the only country without nuclear weapons to enrich uranium to 60 percent, close to the 90 percent threshold theoretically required for a bomb.

Iran's near-bomb-grade uranium stockpile was "a matter of serious concern", it said in its report, adding that its verification after five months of no access to it "is long overdue".

"It is critical that the agency is able to verify the inventories of previously declared nuclear material in Iran as soon as possible in order to allay its concerns and ensure compliance" with the nuclear non-proliferation treaty (NPT) safeguards agreement, the report said.

"The re-establishment of the current status of such inventories... needs urgently to be addressed," it added.

- 'Special report' -

Tehran ratified the NPT in 1970, committing it to declare its nuclear material to the IAEA.

In its quarterly report, the IAEA also said that the NPT safeguards agreement requires Iran to produce a "special report without delay on the status... of the nuclear material and facilities affected by the military attacks".

IAEA head Rafael Grossi said in the report he "has made clear to Iran that it is indispensable and urgent to implement safeguards activities in Iran in accordance with the NPT", saying its implementation "cannot be suspended under any circumstances".

Western powers and Israel have long accused Iran of seeking to acquire nuclear weapons, a claim Tehran denies.

Before the conflict, the IAEA said it had "no indication" of the existence of a "systematic programme" in Iran to produce a nuclear weapon.

Last week, Grossi told French radio RTL that the June strikes on Iran were "devastating", adding that they had "considerably" delayed Tehran's ability to acquire nuclear weapons.

"That does not mean that Iran no longer has the capabilities. Once a country reaches a threshold of knowledge and technological capabilities, they can be rebuilt," Grossi was quoted as saying.

The latest IAEA report comes as nuclear talks between Iran and world powers are stalled.

A now-defunct 2015 deal curbed Tehran's nuclear programme in exchange for sanctions relief.

But it had begun to unravel after Donald Trump in 2018 unilaterally withdrew the United States from the landmark deal with Tehran during his first term as president.

kym/phz

RTL GROUP