The U.S. military has blamed human error for a September air strike in Syria that reportedly killed dozens of Syrian soldiers, but said there was no violation of the international laws of war.
The conclusions about the attack were contained in a report issued November 29 by the U.S. Defense Department.
The September 7 attack prompted outrage from Syria and its main military backer, Russia, which accused Washington of deliberately targeting Syrian forces.
But the U.S. military investigators concluded that soldiers believed they were directing attacks on Islamic State fighters. Because this was an honest mistake, the report found, the strikes did not violate the international law of armed conflict.
Ultimately, the strikes were halted when a Russian military officer called a special telephone hotline to alert the Americans that the strikes near Deir el-Zour were hitting Syrian government forces.
Military investigators suggested that the Russian officer chose to wait 27 minutes to relay his message until he could speak to a familiar U.S. counterpart on the line.
If the message had not been delayed 27 minutes, nearly half of the 30-plus strikes might not have been conducted, the report concluded.
There was no immediate reaction to the U.S. report from Moscow.