At least one bomb used in the Israeli strike that killed dozens of people, including women and children, in a United Nations school building on Thursday appeared to have been made in the United States, according to a weapons expert and videos reviewed by The New York Times.

The school, located in Nuseirat, in central Gaza, was being used as a shelter for thousands of displaced Palestinians. The Israeli military said it had targeted classrooms that were occupied by Palestinian militants, though it did not provide evidence for this claim.

A video of munitions debris, filmed by the Palestinian journalist Emad Abu Shawiesh, shows remnants of a GBU-39 bomb, which is designed and manufactured by Boeing. The use of this weapon in the strike was first reported by CNN.

The footage was uploaded to Instagram shortly after 4 a.m. in Gaza on Thursday, about two and a half hours after the strike was reported on Telegram, a messaging app. The Times, using details seen in videos, confirmed the weapon debris was filmed at the U.N. school.

Trevor Ball, a former U.S. Army explosive ordnance disposal technician, identified the part of the weapon seen in the footage as the nose of a GBU-39. “This distinct nose is unique to the GBU-39 munition series, and, due to its solid construction, it can survive the blast intact,” he said.

The holes visible across several floors of the U.N. compound also suggest the use of a smaller precision-guided munition like the GBU-39, Mr. Ball added.