The US military said it may have unintentionally struck Syrian troops while carrying out a raid against ISIS on Saturday, which if confirmed would mark the first known direct American strike on President Bashar Assad's forces, the AP reports. US Central Command said the strike was immediately halted "when coalition officials were informed by Russian officials that it was possible the personnel and vehicles targeted were part of the Syrian military." The Syrian military said the airstrike hit a base in the eastern city of Deir el-Zour that is surrounded by ISIS, allowing the extremists to advance. Russia's military said it was told by the Syrian army that at least 62 soldiers were killed in the air raid and more than 100 wounded.
"Coalition forces would not intentionally strike a known Syrian military unit," according to a statement from the US military. The Syrian military called the strike a "serious and blatant attack on Syria and its military" and "firm proof of the US support of [ISIS] and other terrorist groups." "The coalition will review this strike and the circumstances surrounding it to see if any lessons can be learned," the US Central Command statement said. The apparently errant strike could deal a crushing blow to a fragile US and Russian-brokered cease-fire that has largely held for five days despite dozens of alleged violations on both sides. (More Syria stories.)