A senior intelligence officer at United States Central Command asked military analysts for "creative and unconventional" ways to pressure and punish Iran in an email sent on 29 July, an unusual brainstorming request that underscores the limits of the six-month air campaign.
US forces have prepared strikes on deeply buried nuclear sites including Pickaxe Mountain, but conventional weapons are seen as insufficient and a ground operation carries heavy risk. The CIA and Defense Intelligence Agency have concluded that further bombing is unlikely to alter Tehran's negotiating stance. Eighteen US service members have been killed in the conflict so far.
President Donald Trump threatened massive strikes over the weekend before standing down following intervention by Saudi Crown Prince Mohammed bin Salman and other Gulf leaders. Trump has said negotiations on the Strait of Hormuz and Iran's nuclear programme could begin soon, though Tehran says it is holding no direct talks with Washington.