Transcript for US drops 'mother of all bombs' in Afghanistan
week" Sunday morning from south Korea. That major news out of Afghanistan. The U.S. Hitting ISIS with the largest nonnuclear weapon ever dropped and ABC's Terry Moran is in London. Has the latest for us. Good morning, Terry. Reporter: Good morning. Afghan witnesses beliliving in areas miles away said they could feel the Earth shake and it's been seen around the world as a message about American firepower to other adversaries. This is the type of bomb the U.S. Used to strike at ISIS in eastern Afghanistan. In this test video you can see it's so huge it's got to be dropped out of the hold of a c-130 cargo plane tethered to a parachute before striking its target in a massive show of force. This was the right weapon against the right target. Reporter: Called a mother of all bombs but its nickname, moab, it's the largest nonnuclear bomb the U.S. Has ever dropped in combat. The target a series of cave complexes in the Achin district well suited to the rugged terrain and an air force spokesperson said one reason it was chosen was for maximizing the destruction of ISIS positions. We are so proud of our military and it was another successful event. Reporter: President Donald Trump praised the operation. Turns out he didn't officially authorize the bomb itself. What I do is authorize my military. We have the greatest military in the world and they've done a job as usual. So we have given them total authorization. And that's what they're doing and, frankly, that's why they've been so successful lately. Reporter: It did not require presidential approval. Top military commanders received newly enhanced authority to fight ISIS in Afghanistan during the Obama administration including deciding what weapons to use. President trump was asked if the use of the mother of all bombs was meant to send a message to North Korea. I don't know if this sends a message. It doesn't make any difference if it does or not. North Korea is a problem. The problem will be taken care of. I will say this, I think China has really been working very hard. Reporter: Well, the use of this huge bomb along with the U.S. Missile trike in Syria and deployment of the "Uss Vinson" are signs of a more muscular doctrine. That is what we're seeing. Thanks very much.
This transcript has been automatically generated and may not be 100% accurate.