With those strikes, Washington joined Israel's bombardments of Iran's nuclear programme in the 12-day conflict launched on June 13.

Israel said its campaign was aimed at ending Iran's nuclear programme, which Tehran insists is for civilian purposes but which Washington and other powers insist is aimed at acquiring atomic weapons.

Here is an overview of the different positions on the strikes.

- US hails 'historic success' -

The Trump administration on Thursday insisted the operation had been a total success, berating journalists for having reported on an intelligence assessment that took a more conservative line.

President Donald Trump "created the conditions to end the war, decimating -- choose your word -- obliterating, destroying Iran's nuclear capabilities", Defense Secretary Pete Hegseth told journalists at the Pentagon.

Trump himself has called the strikes a "spectacular military success", insisting they "obliterated" the nuclear sites, setting Iran's programme back by "decades".

Earlier this week however, US media reported on a leaked preliminary US intelligence assessment that said the strikes had only set back Iran's nuclear programme by months -- coverage sharply criticized by Hegseth and others.

The document was "leaked because someone had an agenda to try to muddy the waters and make it look like this historic strike wasn't successful", Hegseth said.

He also highlighted a statement by CIA chief John Ratcliffe, who pointed to a "historically reliable and accurate" source of information indicating that "several key Iranian nuclear facilities were destroyed and would have to be rebuilt over the course of years".

- Israel claims 'significant hit' -

The Israeli military has said it had delivered a "significant hit" to Iran's nuclear programme.

While it said its attacks had delayed the programme "by several years" it also said it was "still early to assess the results of the operation".

Israeli Prime Minister Benjamin Netanyahu on Tuesday hailed a "historic victory" in the 12-day conflict and vowed to thwart "any attempt" by Iran to rebuild its nuclear programme.

- 'Nothing significant': Khamenei -

Iran's supreme leader Ayatollah Ali Khamenei has hailed what he described as Iran's "victory" over Israel.

"The American president exaggerated events in unusual ways," Khamenei said, insisting the strikes had done "nothing significant" to Iran's nuclear infrastructure.

Iran's Foreign Minister Abbas Araghchi however called the damage "serious" and said a detailed assessment was under way.

Doubts remain about whether Iran quietly removed more than 400 kilogrammes (880 pounds) of uranium enriched to 60 percent from its most sensitive sites before the strikes -- to hide it elsewhere in the country.

The stockpile could in theory produce more than nine atomic bombs -- if the enrichment level were raised to 90 percent.

A Khamenei adviser, Ali Shamkhani, has said that the country still had its stockpile.

"Even if nuclear sites are destroyed, game isn't over, enriched materials, indigenous knowledge, political will remain," he said in a post on X.

UN nuclear watchdog the International Atomic Energy Agency (IAEA), has called for its inspectors to be able to return to Iran's nuclear sites in a bid to account for the stockpiles.

But on Thursday, the Iranian body tasked with vetting legislation approved a bill passed by lawmakers suspending cooperation with the IAEA. That will go to Iran's president for final ratification.

- 'Enormous damage' IAEA -

All sides, even some voices in Tehran, agree the strikes on Fordo, Natanz and Isfahan caused major damage.

"I believe annihilated is too strong. But it (Iran's nuclear programme) has suffered enormous damage," IAEA head Rafael Grossi told French radio RFI.

"It is true that, with its reduced capacities, it will be much more difficult for Iran to continue the pace it had."

Thousands of centrifuges -- the machines used to enrich uranium -- were no longer operational, he said, "given the explosive payload utilised and the extreme vibration-sensitive nature" of the equipment.

Experts say that some centrifuges were stored in unknown locations in recent years, as Iran's cooperation with the UN agency deteriorated.

Other sites of the nuclear programme remain intact.