Satellite image dated June 24, showing damage at the Fordow enrichment facility - Maxar Technologies

Early US intelligence assessments appear to have challenged Donald Trump’s claim that his bombing campaign “totally obliterated” Tehran’s nuclear weapons programme.

The Pentagon’s Defence Intelligence Agency, according to sources, suggests the attack had only set back Iran’s ability to produce the bomb by a matter of months.

Yet there remains a string of questions that analysts must still answer before firm conclusions can be reached.

For example, one of the sources cited by the Washington Post, who was familiar with the initial DIA report, said its conclusions were “low confidence” in nature.

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This is spy speak for conclusions drawn from scant or fragmented evidence, or indicating concerns with sourcing.

The dossier reportedly said that centrifuges used to enrich uranium that could be used in weapons remained intact.

Other findings included that entrances to two of the facilities were sealed off but that underground structures had not been destroyed, and that enriched uranium had been moved to other locations.

Sir Richard Dearlove, the former head of MI6, said it was too early to make a concrete assessment of damage to facilities buried so far underground.

“Has someone shot their mouth off and I mean, what would they know?” he said. “Nothing from overhead is going to tell you what the consequences of the attack are because it’s deep underground.”

A satellite image shows damage to the tunnel entrances of the Isfahan nuclear site - MAXAR TECHNOLOGIES

Early assessments of damage include analysis of satellite imagery.

Commercially available pictures show six deep holes around Fordow, one of the most fortified sites, buried inside a mountain, with debris spread around the site.

One source said the assessment also included signals intelligence, based on communications between Iranian officials.

Mr Trump referred to intercepts when he spoke with journalists on Thursday morning.

“Two Iranians went down to see it and they called back and they said, ‘This place is gone,’” he said.

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But it could take weeks or months for Iran to conduct its own full damage assessments and for their information to filter into communications channels.

Sir Richard, who led the Secret Intelligence Service from 1999 to 2004, said it was unlikely Iran had managed to get people inside the facilities to assess damage “because of the problems of radiation and leaks”.

He said the fact that it had come out in the public domain so rapidly raised another red flag.

“It does sort of politicise the whole thing as well,” he said. “I mean, it does remind me of some of the stuff around Iraq going way back, and some of those reports that came out, and the arguments about them and the difficulty of sourcing, I just don’t think people really know.”

Satellite image dated June 24 of the Fordow nuclear site - MAXAR TECHNOLOGIES

Classified briefings for both chambers of Congress had been expected on Tuesday but were cancelled. A Senate briefing is now expected on Thursday, when top members of Mr Trump’s national security team will have returned from the Nato summit in the Hague, and one for the House will follow the next day.

Chris Coons, a Democratic senator, said the intelligence community needed time to make a detailed assessment.

“This is the key to the question, what’s next? If, in fact, there had been a successful destruction of all of Iran’s dangerous nuclear enrichment program, I’ve said that would have been a significant accomplishment,” he told reporters in the Netherlands for the Nato summit.

“But if this pushes Iran and some of its partners to accelerate their enrichment program, it may have created a more dangerous situation in the region.

“The intelligence community needs the time without political interference to assess the impact and to deliver that assessment to Congress and the president.”

Donald Trump watches the Iran operation from the situation room at the White House - REUTERS

Officials continued to point out the limited nature of the findings so far.

“This is a preliminary, low-confidence report and will continue to be refined as additional intelligence becomes available. We are working with the appropriate authorities to investigate the unauthorised disclosure of classified information,” said a senior DIA official.

The initial Israeli intelligence assessment of the attacks is more optimistic, stating the attacks caused “very significant” damage. However, Mossad has not yet reached a full conclusion.

“A professional battle damage assessment takes time,” an Israeli official told Axios.

“Israeli intelligence services haven’t arrived at any bottom lines for now,” the official added. “But we don’t think there was any bug in the operation, and we have no indications the bunker-buster bombs didn’t work. Nobody here is disappointed.”

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