WASHINGTON (AP) — The U.S. military on Tuesday blamed human error for what it called a mistaken coalition air assault Sept. 17 that reportedly killed dozens of Syrian soldiers. Targeters believed they were directing attacks on Islamic State fighters, and because this was an honest mistake the strikes did not violate the international law of armed conflict, U.S. military investigators concluded.
Multiple opportunities to avoid the mistake were missed in a sequence of events that began with the erroneous identification of a vehicle as belonging to IS and ended when a Russian military officer called a U.S.-Russia telephone hotline to alert the Americans that the coalition strikes near Deir el-Zour were hitting Syrian government forces.
The call prompted the Americans to halt the attacks, but the chief U.S. investigator told reporters at the Pentagon that if word from the Russians had not been delayed 27 minutes, nearly half of the 30-plus strikes might not have been conducted. The Russian caller waited that long for a familiar U.S. counterpart to come on the line before passing his message, investigators said.
"This is unfortunate," the investigators wrote in an executive summary, referring to the 27-minute delay, "but it could have been even more so had the Russians not called." They also said that in notifying Russian officers in advance of the attack, the U.S.-led air operations center inadvertently provided erroneous information about the target location.
"This may have affected the Russian response to the notification and caused considerable confusion in the (targeting) process," the investigation report said.
A request for comment by the Russian Embassy in Washington was not immediately answered.
It was the first known American attack on Syrian President Bashar Assad's forces. Although the Obama administration has called Assad's rule illegitimate, it has focused its military campaign in Syria of forces of the Islamic State group.
The Syrian government said immediately after the attacks that the U.S.-led coalition was guilty of a "serious and blatant attack on Syria and its military," and that it showed the U.S. supports the Islamic State because the assault enabled IS fighters to make important advances on the battlefield. The Russian government, which supports Assad, made a similar statement.
The U.S. denies collusion with IS.
The investigation report released by U.S. Central Command said the targeting errors stemmed from a "reasonable interpretation" of information available at the time.
"Ultimately, we made an unintentional, regrettable error primarily based on human factors in several areas in the targeting process," said Air Force Brig. Gen. Richard Coe, the chief investigator.
Coe said it was not possible to know for sure who was killed in the strikes, but they more than likely were "forces aligned with" the Syrian government. He said it could not be determined with certainty that they were Syrian soldiers, in part because they were not wearing "recognizable" uniforms. The investigation report, which was released in an abbreviated form after Coe spoke, said the targeted individuals wore "a mix of traditional wear, civilian attire and military style clothing that lacked uniformity."
Coe said investigators confirmed 15 deaths but believe there were more. He said outside observers say more than 80 people died.
Asked whether the Obama administration intended to apologize to Syria, Pentagon press secretary Peter Cook said that if Syrian government troops were killed, the U.S. regrets that, but he stopped short of offering an apology.
Among the most striking examples of a missed opportunity to halt the attacks before they began was a statement attributed to an intelligence analyst reviewing video surveillance of the vehicle that was being tracked near Deir el-Zour. Others involved in monitoring the scene had already concluded that it was an IS vehicle, based on the appearance of its occupants.
Coe quoted the unidentified intelligence analyst as saying prior to the decision to attack, "What we're looking at can't possibly be ISIL," using an acronym for the militant group.
"At the time," Coe said, "that analysis was not pushed to a larger group or to the final decision makers."
When the vehicle reached a group of other fighters in the area and was treated as friendly, the coalition analysts watching the events for many hours concluded that all present must be Islamic State fighters. The dissenting analysts' opinion was that the vehicle was a tank and therefore unlikely to be part of the IS force. Other analysts, however, noted that IS had recently commandeered a Syrian army tank, so they dismissed the dissenters' conclusion, Coe said.
The attack went ahead. A total of 34 precision-guided munitions were fired from a variety of warplanes, plus 380 round of 30mm ammunition, Coe said.
The U.S., Australia, Denmark and Britain participated in the attacks, and all four countries had a hand in the investigation led by Coe. U.S. Central Command released only four pages of the investigation report, and those were heavily censored.