WASHINGTON — Senate Democrats accused Secretary of Defense Pete Hegseth of ignoring the risk to civilians in combat operations and demanded he disclose whether the United States was responsible for a deadly attack on an elementary school in Iran.

A majority of Senate Democrats sent a letter to Hegseth on Wednesday calling for a “swift investigation” of an attack on a naval base and elementary school in southern Iran on Feb. 28. The school was mostly destroyed by the strike and at least 175 people, most of them children, were killed.

President Donald Trump has claimed without evidence that Iran carried out the strike. But mangled fragments purportedly recovered from the attack in Minab appear to be from an American-made Tomahawk cruise missile, according to an analysis by The New York Times.

The Pentagon has said the attack was under investigation, but has not given a timeline on when the findings would be released.

The strike drew global condemnation, including from the United Nations, which called it a violation of international humanitarian law.

Senate Democrats said they want the Pentagon to inform them by next week whether U.S. forces carried out the strike.

“There must be a swift investigation into the strikes on this school and any other potential U.S. military actions causing civilian harm, and the findings must be released to the public as soon as possible, along with any measures to pursue accountability,” they wrote.

The Pentagon did not respond to a request for comment.

Sen. John Kennedy of Louisiana was the lone Republican to condemn the attack.

“I think we screwed up,” he said in an interview Tuesday. “I think we made a mistake. It was a terrible, terrible mistake.”

But no Republicans signed onto the request, and Democrats have no official mechanism to force compliance.

Every senator who caucuses with Democrats except Sen. John Fetterman of Pennsylvania signed onto the letter to Hegseth. A group of House Democrats is preparing a similar request to the Defense Department for a report to lawmakers on the deadly school strike.

Several Republicans declined to comment until after the Pentagon concluded its investigation.