US officials said they had intelligence of a possible Islamic State attack on the evacuation operations at Kabul airport, and launched a missile from a drone at a target that was thought to be a car laden with munitions.

In fact, they struck a family that included an Afghan man who worked for a US aid group and seven children. In early November, an initial report carried out by the US Air Force inspector general, Lieutenant General Sami Said, called the strike tragic, but "an honest mistake."

The review by Central Command head General Kenneth McKenzie Jr. and Special Operations Command chief General Richard Clarke made use of Said's report and detailed recommendations on procedures for future drone strikes. But it made no call for anyone to be punished for the mistake.

"What we saw here was a breakdown in process, in execution and procedural events, not the result of negligence, not the result of misconduct, not the result of poor leadership," said Kirby. If Austin "believed... that accountability was warranted, he would certainly support those kinds of efforts," Kirby added.

Compensation payments 

The strike killed Zemari Ahmadi, an employee of US-based Nutrition and Education International, and nine members of his family. Last month, NEI founder and president Steve Kwon called the Pentagon's investigation into the incident "deeply disappointing and inadequate."

The Pentagon promised to pay compensation and also to help relocate family members and Afghans working for NEI overseas, but that remains stuck on determining just who qualifies, according to officials.

Kirby said they are still discussing arrangements with Kwon. "We are working very hard with him and his organization to effect the relocation of the family members," Kirby said.

"We want to make sure we do it in the most safe and responsible way, so that we know it's getting to the right people and only to the right people." Afghanistan's Taliban government Tuesday urged the US to reverse its decision not to punish personnel.

"If there is any justice and regard for human rights and respect for human dignity, then it's their responsibility to punish the culprits and compensate the victims," said spokesman Bilal Karimi.

Kirby refused to comment on a New York Times story Monday that detailed a secret US military unit that launched drone strikes on Islamic State targets in Syria and had a callous attitude toward civilian deaths.

"We take issues of civilian harm very seriously," Kirby said. "And when we don't get it right, we want those mistakes investigated."