Four Democratic senators say they are investigating whether the Pentagon left U.S. troops at a command post in Kuwait without sufficient protection ahead of an Iranian drone attack that killed six American servicemembers and left more than 20 wounded. 

The probe comes after soldiers stationed at the base told CBS News they were left dangerously exposed at a location that was a known target for Iranian drones. Speaking publicly for the first time earlier this month, members of the targeted unit offered CBS News a detailed account of the attack, which occurred on the first day of what has extended into a monthslong conflict between the U.S. and Iran. 

In a letter to Defense Secretary Pete Hegseth, four Democrats on the Senate Armed Services Committee questioned the Pentagon's preparations and whether the administration "failed to protect Americans in the region from Iranian retaliation". 

At a press conference the day after the attack, Hegseth described the Iranian drone as a "squirter" that "happened to hit a tactical operations center that was fortified, but these were powerful weapons." 

Some of the survivors, members of the Army's 103rd Sustainment Command, disputed Hegseth's account. 

"Painting a picture that 'one squeaked through' is a falsehood," one of the injured soldiers told CBS News. "I want people to know the unit … was unprepared to provide any defense for itself. It was not a fortified position." 

The tactical operation center was similar to structures commonplace during the wars in Iraq and Afghanistan — before the rise of drone warfare. Steel-reinforced concrete barriers known as T-walls surrounded the building. These types of barriers are designed to shield service members from the blast of a mortar or rocket but offer no protection from aerial attacks.

"It's just kind of a classic, older military base," one soldier recalled. "Some small barriers. There's a bunch of little tin buildings where we can set up makeshift offices."

Video of the aftermath of the drone strike shows smoke billowing from the building, fires smoldering. Surviving service members described a grisly scene, with their fellow soldiers bleeding heavily from shrapnel wounds and dealing with severe head injuries.  

The senators — New York's Kirsten Gillibrand, Elizabeth Warren of Massachusetts, Richard Blumenthal of Connecticut, and Arizona's Mark Kelly — are seeking information about risk assessments related to the Kuwaiti post ahead of the start of the war. One of the soldiers told CBS News they saw intelligence showing the post was on a list of potential Iranian targets. 

"Secretary Hegseth sent our troops to fight in Iran, refused to take basic steps to protect them, and then tried to cover up his failures when service members died," Warren said in a statement. "Hegseth's leadership has been one betrayal after another — he must be held accountable." 

The Defense Department declined to comment, citing an active investigation into the incident. In a post on X addressing prior CBS News reporting on the attack, Assistant Secretary of Defense Sean Parnell said "every possible measure has been taken to safeguard our troops — at every level."

Hegseth is set to testify before the Senate Armed Services Committee Thursday, following testimony before a House panel on Wednesday.