US BUNKER - BUSTER WEAPONS DWINDLING AS IRAN DIGS DEEPER UNDERGROUND

What happened: A CSIS analysis says the U.S. may have only a few GBU-57 Massive Ordnance Penetrator bombs left, as Iran digs facilities deeper underground. Trump is reportedly weighing use of the GBU-43/B "mother of all bombs." Key numbers: Air Force dropped 14 GBU-57s in Operation Midnight Hammer in June 2025. Why it matters: CSIS warns existing U.S. weapons may be insufficient for the most hardened sites, and new bombs take years to arrive. CENTCOM's Adm. Brad Cooper has called for more investment in weapons able to strike deep underground targets.

A CSIS analysis says the U.S. may have only a few GBU-57 Massive Ordnance Penetrator bombs left, as Iran digs facilities deeper underground. Trump is reportedly weighing use of the GBU-43/B "mother of all bombs."

CSIS warns existing U.S. weapons may be insufficient for the most hardened sites, and new bombs take years to arrive. CENTCOM's Adm. Brad Cooper has called for more investment in weapons able to strike deep underground targets.