Iran’s nuclear programme has been "degraded" by up to two years as a result of recent US airstrikes, Pentagon spokesman Sean Parnell said.
"We have degraded their programme by one to two years. At least, intel assessments inside the department assess that. We're thinking probably closer to two years," Parnell told reporters on Wednesday.
He said the US assessment on the damage inflicted on three key Iranian nuclear facilities remains "unchanged", describing the sites as "completely obliterated".
"We believe that Iran's nuclear capability has been severely degraded, perhaps even their ambition to build a bomb," he said, adding that assessments are "ongoing".
According to the Pentagon, the US dropped six bunker-buster bombs on the Fordo nuclear facility on June 22 and launched dozens of submarine-based cruise missile attacks on two other sites in Natanz and Isfahan.
The strikes were part of a broader campaign targeting Iran’s nuclear programme.
A sixth round of US-Iran talks had been scheduled for June 15, but Israeli air strikes on Iranian military, nuclear and civilian sites on June 13 triggered a wider conflict.
The 12-day conflict between Israel and Iran ended with a US-sponsored ceasefire that came into effect on June 24.
"The Department of Defense will support the diplomatic mission to continue that peace by ensuring that we maintain capability across the Middle East," said Parnell.
He added that President Donald Trump and Defence Secretary Pete Hegseth have "a range of military options available" to defend US citizens, troops and regional assets.
"We don't have any force posture updates at this time in the CENTCOM AOR (area of responsibility)," he said.
Effectiveness of US strikes
Debate continues over the effectiveness of the US strikes that targeted three Iranian nuclear sites on January 22.
While recent American intelligence reports have affirmed the success of the operation, initial Iranian assessments claimed the damage was limited.
Iranian sources said the impact was "minor" and noted that enriched uranium had been moved from the targeted sites in advance, suggesting Iran may have anticipated the attacks.
The differing narratives have fuelled speculation over the long-term effects on Iran’s nuclear programme.
In a notable shift, Iranian Foreign Minister Abbas Araghchi acknowledged that the US bombing caused "severe and extensive damage" to the Fordo nuclear facility.
"No one knows exactly what happened inside Fordo. What we do know so far is that the US bombing caused severe and extensive damage to the nuclear site," Araghchi told CBS News.
He said Iran’s Atomic Energy Organisation is currently conducting an evaluation and will submit a report to the government.
US condemns IAEA pullout
Meanwhile, the US State Department on Wednesday condemned Iran’s decision to suspend cooperation with the International Atomic Energy Agency (IAEA), calling it "unacceptable".
Earlier, Iranian authorities suspended cooperation with the IAEA, according to state media.
The decision came after President Masoud Pezeshkian reportedly informed government bodies that cooperation would cease unless security at Iran’s nuclear facilities could be guaranteed.
The move follows legislation passed by Iran’s parliament and approved by the Guardian Council in response to the 12-day conflict and attacks on nuclear sites.