US military did not use its powerful bunker-buster bombs on Iran's Isfahan nuclear facility in the recent Operation Midnight Hammer, Joint Chiefs of Staff Chairman General Dan Caine has confirmed. During a classified briefing to senators on Thursday, Gen. Caine explained that the Massive Ordnance Penetrator (MOP), the US military's biggest conventional bomb made to blast deep underground bunkers, wasn't used on Isfahan since the site is too deep underground for the bomb to be completely effective.

Only Tomahawk cruise missiles were used to attack Isfahan, where some 60 per cent of Iran's stockpile of enriched uranium is believed to be stored, US officials said in a briefing to lawmakers. The attack was part of a wider operation intended to disrupt Iran's nuclear program, which is said by Washington to threaten the development of nuclear weapons. Contrarily, the Pentagon confirmed that bunker-buster bombs were extensively utilised against Iran's Fordow and Natanz nuclear sites. Under a top-level Pentagon briefing, US Defence Secretary Pete Hegseth and Gen. Caine presented dramatic footage of the employment of the GBU-57 A/B MOP bombs. "Fordow was our top target. It was thought to be untouchable, but the plant has now been destroyed," Gen. Caine told reporters. Six ventilation shafts into the mountain were demolished with pinpoint strikes, he added.

Iran Nuclear Programme Set Back By Months

An initial Defense Intelligence Agency (DIA) report indicated the attacks have pushed Iran's nuclear plans back by a few months. US President Donald Trump and his officials claimed that the attacks had "obliterated" Iran's central nuclear capabilities. Discussing Truth Social, Trump stated, "Fordow is gone. We have eliminated the key hub of Iran's uranium enrichment." Despite Pentagon confirmation of the success of the operation, there is still doubt about whether Iran can have transferred its stockpile of enriched uranium ahead of the attacks.

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Defense Secretary Hegseth declined to confirm whether the reported 880 pounds of enriched uranium at Isfahan were destroyed or had been moved out. I'm not aware of any intelligence that suggests things were moved, but we are reviewing all aspects," Hegseth stated. The US Defense Threat Reduction Agency took more than 15 years to develop the GBU-57 MOP bomb specifically to penetrate far underground nuclear bunkers such as Fordow. Gen. Caine added that the programme involved huge supercomputing resources and testing for years.

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Iran's missile attacks killed 28 Israelis, according to official numbers reported by the Israeli government. Meanwhile, Iranian health officials said that Israeli airstrikes in Iran killed at least 627 civilians. The revelations by General Dan Caine represent a new chapter in the rhetoric between Israel and Iran, highlighting Washington's overt military engagement to challenge Iran's nuclear program.