36 ISIS fighters killed in massive bomb blast

Afghan officials say 36 fighters with the Islamic State group were killed in a U.S. attack on a tunnel complex in a remote eastern part of the country, near the Pakistan border.

The bomb, dropped Thursday, was the largest non-nuclear weapon ever used in combat by the U.S. military. Afghan officials say there were no civilian casualties.

The bombing came just days after a Green Beret was killed fighting ISIS there, the U.S. Defense Department announced.

A U.S. Air Force C-130 cargo plane dropped the GBU-43B, a 21,000-pound conventional bomb, on an ISIS tunnel complex in Nangarhar Province.

The MOAB -- Massive Ordinance Air Blast -- is also known as the "Mother Of All bombs." It was first tested in 2003 but hadn't been used in combat before Thursday.

"As ISIS-K's losses have mounted, they are using IEDs, bunkers, and tunnels to thicken their defense," Gen. John Nicholson, the U.S. commander in Afghanistan, said in a statement. "This is the right munition to reduce these obstacles and maintain the momentum of our offensive against ISIS-K."

ISIS-K refers to the group's Khorasan offshoot, which operates in Pakistan, Afghanistan, and other parts of South Asia.

The MOAB "targeted a system of tunnels and caves that ISIS used to move around freely," White House Press Secretary Sean Spicer said. The strike was designed to deny ISIS "operational space."

The military said the strike was designed to minimize risk to U.S. and allied Afghan forces while maximizing the effect on ISIS fighters and facilities.

Special Forces Staff Sgt. Mark De Alencar died in combat on April 8 in the same province, but a U.S. defense official told Fox News the bombing had nothing to do with his death.

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