Last Thursday, the United States deployed its largest non-nuclear weapon against an underground ISIS stronghold in Afghanistan.  The MOAB, or Massive Ordnance Air Blast bomb (also known as the GBU-43/B) was dropped from the back of an Air Force C-130 at just after 19:30 local time and was intended to destroy the underground structure, eliminating enemy combatants hidden inside and limiting the risk to U.S. and Afghan forces tasked with clearing the region.

Intelligence reports suggested that between 600 and 800 Islamic State fighters were active in the area and using the tunnel system as a base of operations, and at least one U.S. service member, Staff Sergeant Mark R. De Alencar, 37, of Edgewood, Maryland, was killed in recent weeks when jihadis ambushed his special operations unit from within one of the tunnels.

“As ISIS-K’s losses have mounted, they are using [improvised bombs], bunkers and tunnels to thicken their defense,” said Army Gen. John W. Nicholson, commander of U.S. Forces Afghanistan, on the decision to drop the MOAB. “This is the right munition to reduce these obstacles and maintain the momentum of our offensive against ISIS-K.”

ISIS-K is also sometimes referred to as the Khorasan group, and is composed primarily of former members of Tehrik-e Taliban Pakistan and the Afghan Taliban that operate out of the Afghanistan-Pakistan region.