WASHINGTON — The acting secretary of defense, Patrick M. Shanahan, is reviewing internal awards and punishments that were given to soldiers as a result of last year’s Pentagon investigation into a deadly 2017 ambush in Niger.
Earlier recommendations for the citations by Jim Mattis, the former defense secretary, were not sufficient, Mr. Shanahan told lawmakers on Tuesday.
“I convened my own review so I can ensure, from top to bottom, the appropriate accountability,” Mr. Shanahan said in testimony to the House Armed Services Committee.
During the hearing, Representative Ruben Gallego, Democrat of Arizona, needled Mr. Shanahan about the ambush, which killed four American soldiers. In a statement afterward, he called it “unreasonable for a review of the Niger ambush — a catastrophe now two years old — to still be pending, let alone for a new review to be started at this late date.”
Mr. Shanahan did not give a timeline for his review, saying only that it would end soon.
In May, United States Africa Command finished an initial investigation into the ambush and found widespread problems across the military operation. That inquiry focused mostly on the actions of junior officers before an hourslong gun battle against dozens of Islamic State militants.
A separate investigation, by Special Operations Command, has been in limbo as high-ranking Defense Department officials have been divided on its outcome. It largely sought to overhaul training protocols but also designated soldiers for awards for valor and for punishments.
In December, before he left the Pentagon, Mr. Mattis criticized Defense Department officials for the length of the investigation and the fact that most of the resulting punishments were issued against junior officers with relatively little experience.
The Army has since punished officers and enlisted soldiers who were involved in the battle at nearly every level of command, like a captain, who was the Green Beret team leader in the ambush, and the two-star general who oversaw all Special Operations Forces in Africa. The punishments focused primarily on training failures that led up to the attack on Oct. 4, 2017.
Col. Bradley D. Moses, then the commander of the Third Special Forces Group, is the one of the only people in the Special Operations chain of command involved in the ambush who remains unpunished.
The Pentagon has yet to deliver a redacted version of the initial investigation to the public and to the families of the soldiers who died, as promised by Gen. Thomas D. Waldhauser, the leader of Africa Command. The Pentagon released a short summary of its investigation in May.