The Pentagon said Thursday US forces in Afghanistan dropped the military’s largest non-nuclear bomb on an Islamic State target in Afghanistan.

Pentagon spokesman Adam Stump 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 US Air Force calls it the Massive Ordnance Air Blast bomb, or MOAB.

Based on the acronym, it has been nicknamed the “Mother Of All Bombs.”

The strike occurred at about 7:32 p.m. local time (15:02 GMT).

Stump said the bomb was dropped on a cave complex believed to be used by IS fighters in the Achin district of Nangarhar province, very close to the border with Pakistan.

“As ISIS-K’s losses have mounted, they are using IEDs, bunkers and tunnels to thicken their defense. This is the right munition to reduce these obstacles and maintain the momentum of our offensive against ISIS-K,” said US General John W. Nicholson, commander of American forces in Afghanistan, in a statement.

“US Forces took every precaution to avoid civilian casualties with this strike. US Forces will continue offensive operations until ISIS-K is destroyed in Afghanistan,” the US army said in a statement.

Referring to the Islamic State, White House spokesman Sean Spicer said: “We must deny them operational space, which we did.”

The MOAB was rapidly developed in 2002-2003 around the time of the US-led invasion of Iraq.

According to the Air Force, the last time the MOAB was tested in 2003, a huge mushroom cloud could be seen from 20 miles (32 kilometers) away.

The satellite-guided weapon is so large it is rolled off a transport aircraft rather than dropped from the weapons bay of a bomber. It is partially used to intimidate enemy forces after the noted success of its predecessor, the BLU-82 bomb, which dates back to the Vietnam war where it was used to clear jungle areas for helicopters.

Screen shot from video of a Massive Ordnance Air Blast bomb (MOAB) test. (YouTube/Military Forces)

Screenshot from a video of a Massive Ordnance Air Blast bomb (MOAB) test. (YouTube: Military Forces)