The United States military did not use the “bunker-buster” bombs on Iran’s Isfahan nuclear facility during last week’s Operation Midnight Hammer, chairman joint chiefs of staff, General Dan Caine, told senators during a classified briefing.The facility is so deep that the bomb – actual name Massive Ordnance Penetrator (MOP) – likely would have not been effective, the general informed senators on Thursday, CNN reported.US officials believe that Isfahan’s underground structures contain nearly 60 per cent of the Islamic Republic’s enriched nuclear stockpile, which Tehran would need in order to ever produce nukes.Only Tomahawk missiles were used to strike Isfahan. On the other hand, the B-2 Spirit bombers dropped more than a dozen bunker-busters on the other two targets – Fordow and Natanz.The classified session was held by Caine, defense secretary Pete Hegseth, secretary of state Marco Rubio and John Ratcliffe, director, CIA. During the briefing, Ratcliffe said that the US intelligence community assesses that the majority of Iran’s enriched nuclear material is buried at Isfahan and Fordow, according to an official.Following the strikes, a preliminary assessment by the Defense Intelligence Agency the attack did not destroy the core components of Iran’s nuclear programme, including its enriched uranium, and likely only set it back by months. The assessment was disputed by members of the Donald Trump administration.President Trump has repeatedly asserted that Iran’s nuclear programme was “obliterated.”