Mullen spoke to ABC's "This Week" a couple of days after the head of the U.S. Central Command Gen. Kenneth F. McKenzie Jr. announced that it is dubious that any ISIS-K members were killed in a Kabul drone strike on Aug. 29, where he was questioned whether there needs to be accountability.
"Absolutely. I think they should. This was obviously an incredibly complex, fast-moving situation. We lost those 13 military members a couple of days before that," Mullen said. "There was clear intelligence that additional strikes were on the way, so it was in that environment in which this strike actually took place."
Mullen, who worked as the chairman of the Joint Chiefs of Staff during the last couple years of the Bush administration and the first couple years of the Obama administration, said the botched drone strike was a "tragic, tragic mistake" and said he thought McKenzie did the right thing by confessing. He also cited that Secretary of Defense Lloyd Austin committed to a study that he believes will bring "accountability."
ABC's Martha Raddatz came up to cite how the Pentagon took several days to confirm they made a mistake after a New York Times report detailed the intelligence on the ground about innocent children being killed.
"I think you're going to want to try to get this right," Mullen said. "Clearly they were convinced at the time it was a good strike, and it takes some time to do that, and this is the same command that's been evacuating Afghanistan and all that that entails. I'm not overly concerned about how long it took."
By the end of the segment, Raddatz asked Mullen whether there should be accountability for the Biden administration's withdrawal from Afghanistan that resulted in 13 U.S. service members being killed in the Kabul airport suicide bombing.
"I also think there should be accountability there as well," Mullen said. "I hope there is."
Joint Chiefs of Staff Gen. Mark Milley earlier this month argued that the drone strike that killed an aid worker and up to nine of his family members, including seven children, was a "righteous strike," but he walked back that comment Friday by saying it was a "horrible tragedy."
"In a dynamic high threat environment, the commanders on the ground had appropriate authority and had reasonable certainty that the target was valid but after deeper post strike analysis our conclusion is that innocent civilians were killed," he said. "This is a horrible tragedy of war and it’s heart wrenching and we are committed to being fully transparent about this incident."