A 400kg stockpile of uranium – enough to make up to 10 nuclear weapons, US Vice President JD Vance told American broadcaster ABC – is unaccounted for after Washington dropped six ‘bunker busters’ on three Iranian nuclear facilities last week. The missing uranium is enriched to 60 per cent. It needs to be enriched to about 90 per cent to be used as a nuclear weapon.

There are reports Iran may have moved the stockpile, as well as some equipment, days before the attack to a secret location, a claim repeated by Israeli officials to The New York Times.

Satellite images from before the US’ strike showed a line of 16 trucks outside the Fordow nuclear plant, which is built deep under a mountain and is considered impervious to most missile attacks, prompting the Israelis to ask the Americans to drop the ‘bunker busters’.

Post-attack images showed signficant damage to the facility but the trucks were missing.

But it is unclear what was moved and where it was moved to.

According to Rafael Grossi, chief of the IAEA – the International Atomic Energy Agency, a global nuclear watchdog – it had been last inspected a week before Israel’s first attack on Iran.

Last week Grossi told the United Nations Security Council it is “essential” the IAEA resumes inspections as soon as possible to ensure the stockpile had not been diverted.

He also warned the world that continued military escalation delays this “indispensable work” and degrades chances of a diplomatic solution to ensure Iran does not acquire a nuclear weapon.

US B-2 ‘Spirit’ bombers dropped the ‘bunker busters’ early Sunday on the Fordow, Natanz, and Isfahan nuclear facilities, marking its entry into the volatile 12-day military conflict.

After the strikes President Donald Trump declared Iran’s nuclear programme had been “completely and totally obliterated” by the ‘bunker busters’ and a barrage of Tomahawk missiles fired as decoys. Trump hailed the 37-hour military operation, which was led by seven B-2 bombers flying radio silent and non-stop from an air base in Missouri to deliver the bombs.