WASHINGTON, D.C. — White House Press Secretary Sean Spicer told reporters on Thursday that the United States dropped the large, powerful GBU-43 bomb on a system of ISIS tunnels and caves in Afghanistan that day in an effort to deny the group “operational space.”

Spicer said at an unusually short afternoon White House press conference:

At around 7 p.m. local time in Afghanistan, the United States military used a GBU-43 weapon in Afghanistan. The GBU-43 is a large, powerful and accurately delivered weapon. We targeted a system of tunnels and caves that ISIS fighters used to move around freely, making it easier for them to target U.S. military advisers and Afghan forces in the area. The United States takes the fight against ISIS very seriously. In order to defeat the group, we must deny them operational space, which we did. The United States took all precautions necessary to prevent civilian casualties and collateral damage as a result of the operation.

Spicer referred reporters to the Department of Defense for more information.

The Pentagon identified the GBU-43 as the military’s largest non-nuclear bomb. It contains 11 tons of explosives and is nicknamed the “Mother of All Bombs.” Pentagon spokesman Adam Stump stated that this was the first ever combat use of this bomb.

The Associated Press reported:

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 is close to Afghanistan’s border with Pakistan, according to the AP report.

A statement from U.S. Forces – Afghanistan said the strike targeted ISIS’s Afghan affiliate, ISIS-Khorasan. The strike was part of ongoing efforts to defeat the group in 2017. “The strike was designed to minimize the risk to Afghan and U.S. Forces conducting clearing operations in the area while maximizing the destruction of ISIS-K fighters and facilities.”

Army Gen. John W. Nicholson said, “As ISIS-K’s losses have mounted, they are using IEDs, bunkers and tunnels to thicken their defense.”

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