From the August 26, 2021, edition of CNN Newsroom with Poppy Harlow and Jim Sciutto

SAM KILEY (CNN SENIOR INTERNATIONAL CORRESPONDENT): We don't yet know officially in any great detail the provenance of this bomb. But all of the fingers of blame are going to be pointing towards ISIS-K. 

And they’re really the only organization, Jim, in the world really, that has an interest in committing this kind of an atrocity, because it does three things: It intimidates the Afghan population, which is very much an ISIS tactic or even strategy. It embarrasses and humiliates the Taliban, who had got a security deal — they were effectively running security in their own way, and filtering out Afghans, counter to American policy — but they were working with the United States. And then you’ve got the United States running security for that multinational coalition effort to get as many people out before they have to start withdrawing themselves.

 … 

They want the publicity. They want the attention, they want to humiliate both the Taliban and the United States, and that’s what they're trying to achieve with this sort of atrocity of this nature.