This photo provided by Eglin Air Force Base shows the GBU-43/B Massive Ordnance Air Blast bomb. The Pentagon says U.S. forces in Afghanistan dropped the military's largest non-nuclear bomb on an Islamic State target in Afghanistan. A Pentagon spokesman said it was the first-ever combat use of the bomb, known as the GBU-43, which he said contains 11 tons of explosives. The Air Force calls it the Massive Ordnance Air Blast bomb. Based on the acronym, it has been nicknamed the "Mother Of All Bombs." (Eglin Air Force Base via AP)

WASHINGTON — U.S. forces in Afghanistan on Thursday struck an Islamic State tunnel complex in eastern Afghanistan with "the mother of all bombs," the largest non-nuclear weapon ever used in combat by the U.S. military, Pentagon officials said.

The bomb, known officially as a GBU-43B, or massive ordnance air blast weapon, unleashes 11 tons of explosives. When it was developed in the early 2000s the Pentagon did a formal review of legal justification for its combat use.

The U.S. military headquarters in Kabul said in a statement that the bomb was dropped at 7:32 p.m. local time Thursday on a tunnel complex in Achin district of Nangarhar province, where the Afghan affiliate of the Islamic State group has been operating.

The target was close to the Pakistani border.

Adam Stump, a Pentagon spokesman, said the bomb was dropped from a U.S. Air Force MC-130 transport, which he said had been brought to Afghanistan "some time ago" for potential use.

Army Gen. John W. Nicholson, commander of U.S. forces in Afghanistan, said in a written statement that the strike was designed to minimize the risk to Afghan and U.S. forces conducting clearing operations in the Achin area "while maximizing the destruction" of IS fighters and facilities. He said IS has been using improvised explosive devices, bunkers and tunnels to strengthen its defenses.

"This is the right munition to reduce these obstacles and maintain the momentum of our offensive against ISIS-K," he added, using the U.S. military's acronym for the IS affiliate.


Become a #ThisIsTucson member! Your contribution helps our team bring you stories that keep you connected to the community. Become a member today.