An American warplane that bombed a hospital in Afghanistan last month and killed at least 30 people, including doctors and patients, was acting on poor intelligence produced by human error, U.S. military officials said this week. The Pentagon was scheduled to release Wednesday the results of an internal investigation that found U.S. forces were aiming for a known Taliban position when they struck the hospital in Kunduz province, the Wall Street Journal reported.

The error happened in part because targeting information was relayed orally instead of by computer. The findings come as Army Gen. John Campbell, the commander of U.S. forces in Afghanistan, weighs whether pilots and special-operations personnel on the ground should face disciplinary action over the hospital bombing Oct. 3.

The hospital was run by the humanitarian organization Doctors Without Borders, aka Medecins Sans Frontieres, or MSF. Doctors Without Borders has said the hospital was intentionally hit and that there were no armed men or fighting in the area at the time of the airstrikes.

“A mistake is quite hard to understand and believe at this stage,” Christopher Stokes, the general director of Doctors Without Borders, said at a news conference in Kabul this month.

But U.S. officials said special-operations forces were acting on information shared by Afghan troops also operating in the area. “There was certainly some confusion over what they were shooting at,” a military official told the Wall Street Journal. “If there wasn’t, then this wouldn’t have happened.”

It’s unclear whether reacting to such informal instructions will be ruled a breach of military operational rules, the New York Times reported. Meanwhile, Doctors Without Borders and others have accused the military of releasing misinformation about the attack in the past.

“As you know, the United States military takes extraordinary steps to avoid harm to civilians,” Campbell said at a Pentagon briefing two days after the incident. “However, the Taliban have purposefully chosen to fight from within a heavily urbanized area, purposely placing civilians in harm’s way.”