Democratic lawmakers have announced an investigation into the Iranian drone strike that killed six U.S. service members at Port Shuaiba, Kuwait, earlier this year, citing concerns over the objectivity and thoroughness of the military’s internal review. The letter, sent Thursday to Defense Secretary Pete Hegseth, was signed by Senator Elizabeth Warren (D-Massachusetts), Representative Pat Ryan (D-New York), and nearly a dozen other members of Congress.

The drone attack occurred on March 1, the second day of Operation Epic Fury—a designation given to the ongoing conflict by the Trump administration—when an Iranian Shahed drone crashed into an Army operations center near the Persian Gulf. In addition to the six fatalities, dozens of troops were injured during the attack.

In their letter, lawmakers questioned whether the military had implemented adequate defenses at the facility before the strike and whether the wounded received proper medical treatment afterward. Some survivors have alleged that commanders failed to act on prior warnings about insufficient security measures, while others have described difficulties obtaining timely medical care. Military officials have disputed these claims.

The lawmakers expressed skepticism about the independence and rigor of the Army’s internal investigation, which was initially conducted by a midgrade officer within the unit involved. The inquiry was later shifted to a more senior officer at U.S. Army Central, the parent command, but critics argue this still falls short of an impartial, external review. According to reporting cited in their letter, early findings from the Army’s probe did not assign fault or recommend disciplinary action. The Army has shared some details with families of the deceased but has not made the findings public.

Senator Warren emphasized that their concerns extend beyond this specific incident, underscoring the need for accountability and protections for service members. The letter also criticized the Defense Department for alleged failures in providing adequate care to injured troops and a lack of transparency in disclosing the war’s consequences.

The Pentagon did not confirm whether it will cooperate with the congressional inquiry, stating only that it responds directly to all communications from Congress. Lawmakers have requested a response by August 12 as they seek to ensure a comprehensive and objective review of the circumstances surrounding the Port Shuaiba attack.