Defense Secretary Ashton Carter on Wednesday pledged openness on allied accountability a day after dozens of civilians were killed in raids near an IS-held town in Syria.
The Syrian Observatory for Human Rights said Tuesday that children were among at least 56 civilians killed in strikes by the coalition as they fled Al-Tukhar in Aleppo province, near the key Islamic State group stronghold of Manbij.
"We will conduct an investigation on any possible civilian casualties in this matter, as we always do, and we'll be transparent about that," Carter told a briefing at this air base outside Washington.
General Joe Votel, head of Centcom said allies would " continue to do all we can to protect civilians from harm," at the same news conference.
"It is an extraordinarily dynamic situation up around Manbij right now, as we talked about a little bit earlier."
The Syrian Democratic Forces, an alliance off militias, has been fighting since May 31 to retake Minbej.
"So it's a very difficult fight. ISIL is trying to hold onto that area, so we do see them showing up at a variety of different locations," Votel said.
"And so when it's a dynamic situation like that... we have to respond. And I think that's the situation in which we found this particular" operation.
Rights groups say war crimes have been committed by all sides in Syria's conflict, which began in March 2011 and has killed more than 280,000 people.
The government is accused of widespread torture, as well as indiscriminate fire on civilian populations.
And the Islamic State jihadist group has regularly carried out gruesome executions of its opponents.
