WASHINGTON — The Army Green Berets who requested the Oct. 3 airstrike on the Doctors Without Borders trauma center in Afghanistan were aware it was a functioning hospital but thought it was under Taliban control, The Associated Press has learned.

The new information adds to a body of evidence that the internationally run medical facility site was familiar to the U.S. military, raising questions about whether the decision to attack it violated international law.

A day before an American AC-130 gunship attacked the hospital, a senior officer in the Green Beret unit wrote in a report that U.S. forces had discussed the hospital with the Afghanistan director of the medical charity group, presumably in Kabul, according to people who have seen the document.

The attack left a mounting death toll, now up to 30 people.

Separately, in the days before the attack, “an official in Washington” asked Doctors without Borders “whether our hospital had a large group of Taliban fighters in it,” said spokesman Tim Shenk in an e-mail. “We replied that this was not the case. We also stated that we were very clear with both sides to the conflict about the need to respect medical structures.”

Taken together, the revelations add to the growing possibility that U.S. forces destroyed what they knew was a functioning hospital, which would be a violation of the international rules of war.

The Pentagon has said Americans would never have intentionally fired on a medical facility. It’s unclear why the Green Beret unit requested the strike — and how such an attack was approved by the chain of command — on coordinates widely known to have included a hospital.

Even if the U.S. thought the Taliban were operating from the hospital, the presence of wounded patients inside would have made an air attack problematic under standard American rules of engagement and the international law of war.

Pentagon spokesman Maj. Roger Cabiness declined to answer questions, saying in a statement that it would be “premature to draw any conclusions” before the three investigations into the attack are complete.

The U.S. has determined “that the reports of civilian casualties were credible, and we continue to work with the government of Afghanistan to fully identify the victims,” said Brig. Gen. Wilson Shoffner, a NATO spokesman, in a statement.

U.S. and NATO investigations, he said, “continue to look at a series of potential human errors, failures of process and technical malfunctions that may have contributed to the mistaken strike on the hospital.”