ISTANBUL

US strikes last month heavily damaged one Iranian nuclear site, while the other two suffered limited damage and could resume enrichment within months, according to a recent American assessment of the destruction caused by the military operation, five current and former officials familiar with the assessment told NBC News.

The operation, conducted under the Trump administration, targeted Iran’s nuclear facilities at Fordo, Natanz and Isfahan.

The attack on Fordo was successful in setting back Iran’s enrichment capabilities there by as much as two years, according to two current officials.​​​​​​​

The other two sites targeted sustained less damage and may have been degraded only to the point where nuclear enrichment could resume within several months if Iran chooses to do so.

The assessment was delivered in recent days to some US lawmakers, Department of Defense officials and allied governments.

NBC News also learned that US Central Command (CENTCOM) had planned a larger strike on Iran targeting three more sites over several weeks, not just one night, according to a current and two former US officials.

President Donald Trump was briefed, but he rejected it, preferring to avoid deeper conflicts and high casualties, one of the current officials and one of the former officials said, according to the report.

“We were willing to go all the way in our options, but the president did not want to,” said one of the sources with knowledge of the plan.

- Pentagon denies report, slams credibility of media coverage

Chief Pentagon spokesman Sean Parnell denied the report, saying it is "false."

"The credibility of the Fake News Media is similar to that of the current state of the Iranian nuclear facilities: destroyed, in the dirt, and will take years to recover," Parnell said on X, sharing the NBC News report.

Last week, officials from the Defense Threat Reduction Agency (DTRA) said the US strikes on the three key Iranian nuclear facilities met their "objectives" but stopped short of confirming whether the sites were completely destroyed, noting that the Battle Damage Assessment (BDA) is still pending.

"We have received initial assessments, and the more completed assessments will come in over time," an official told reporters.

At a news conference on June 22, Air Force Gen. Dan Caine, chairman of the Joint Chiefs of Staff, said initial battle damage assessments indicate that all three sites "sustained extremely severe damage and destruction" during “Operation Midnight Hammer."

Trump said repeatedly that Iran's nuclear sites were "obliterated."

Earlier this month, Parnell told reporters that Iran's nuclear program was "degraded" by one to two years due to the US strikes, noting that the sites were "completely obliterated."

*Diyar Guldogan from Washington, DC contributed to this report