Formal Military Investigation Underway Into Reported Civilian Casualties From Airstrike in Manbij, Syria

— -- The U.S. military announced today that it would undertake a formal investigation into an airstrike in northern Syria that may have resulted in civilian casualties.

“That credibility assessment is complete,” Col. Christopher Garver, the U.S. military spokesman in Baghdad, said during a news conference with Pentagon reporters. “The result was that the information available was credible enough to warrant formal investigation, which we have initiated.”

Garver indicated that evidence used in such investigations comes from both public sources as well as the military’s own internal data, such as reviewing where the rounds struck. “We know where we are shooting,” Garver said.

The death toll estimates from the alleged airstrike near the town of Manbij have varied widely, with Garver saying he had seen numbers in the media ranging from 10 to more than 70. According to local observers and activists, the number could be above 200. ABC News has not been able to independently verify the numbers killed.

Garver also revealed that a second initial investigation is now underway to determine the credibility of allegations surrounding civilian deaths during an alleged strike on July 23rd to the east of Manbij.

More than 520 airstrikes have been conducted by the U.S.-led coalition in support of the battle to rid Manbij of ISIS, according to U.S. officials.