The Pentagon said Tuesday that intelligence errors resulted in a US-led coalition air strike in Syria in September that reportedly killed around 90 Syrian government forces.
There were "errors in the development of intelligence, as well as missed opportunities for coalition members on duty to recognize and voice contrary evidence to decision-makers," the US military's Central Command said in a statement following a six-week probe into the September 17 attack near Deir Azzor.
The US-led coalition is focused on attacking the ISIS group in Syria and Iraq and does not want to get involved in Syria's brutal civil war.
Australian, Danish, British and American planes all took part in the air strike, which the Syrian Observatory for Human Rights monitoring group has said killed at least 90 regime troops.
The Pentagon said it had only been able to conclusively count 15 deaths, but acknowledged the toll was possibly much higher.
"In this incident, we made an unintentional, regrettable error primarily based on human factors in several areas in the targeting process," Brigadier General Richard Coe, who investigated the case, told reporters.
Key among these mistakes was an early misidentification of a Syrian vehicle as belonging to ISIS militants, which colored subsequent intel assessments.
Further complicating matters, the troops were not wearing recognizable military uniforms or carrying identifying flags, the Pentagon said.
Perhaps most significantly, a critical miscommunication occurred when Russian forces called the coalition to tell them the strike was hitting Syrian regime troops.
That call, which came in on a special hotline between the coalition and Russians, was subject to a 27-minute delay because the officer with whom the Russians normally spoke was not immediately available.
During that window, almost half of the 32 separate strikes making up the larger assault occurred.
As soon as the Russians were able to speak to their regular point of contact, the strike was called off.
No coalition forces are being charged in the incident.
"In my opinion, these were a number of people all doing their best to do a good job," Coe said.
"The decision to strike these targets was made in accordance with the law of armed conflict and the applicable rules of engagement."
The strike was conducted by F-16 and FA-18 fighters, A-10 ground-attack craft and drones.SHOW MORE