The “near certainty” standard only applies “when we take direct action ‘outside areas of active hostilities,’ as we noted at the time,” Caitlin Hayden, a spokeswoman for the National Security Council, told Yahoo News.

The statement came in response to inquiries about increasing reports of civilian deaths — including women and children — that resulted from U.S.-led airstrikes in Syria, Yahoo News said. On Sept. 23 a Tomahawk missile struck the Syrian village of Kafr Daryan, killing about a dozen civilians, according to reports.

“They were carrying bodies out of the rubble … I saw seven or eight ambulances coming out of there,” said Abu Abdo Salabman, a political member of a Free Syrian Army faction who attended a briefing for Foreign Affairs Committee members and staff.

Hayden said the U.S. military operations in Syria against fighters from Islamic State in Iraq and the Levant (ISIL), “like all U.S. military operations, are being conducted consistently with the laws of armed conflict, proportionality and distinction.”

International humanitarian laws prohibit the deliberate targeting of civilians, require steps to avoid such casualties and say that military gains from such actions should outweigh any threat to civilians.

One House member present at the Foreign Affairs briefing, Rep. Adam Kinzinger, R-Illinois, spoke to Yahoo News about the reports of civilian deaths in Syria.

“I did hear them say there were civilian casualties, but I didn’t get details,” he said. “But nothing is perfect,” and any deaths from U.S. strikes were “much less than the brutality of the Assad regime.” He was referring to Syrian President Bashar al-Assad, whose government has been battling various rebel groups in an insurgency that has lasted more than three years.

On Monday the Syrian Observatory for Human Rights, a group monitoring the war, said U.S. airstrikes hit a grain silo in northeastern Syria overnight Sunday, killing civilians and wounding fighters. But U.S. officials said the strike on the town of Manbij was in response to intelligence showing Islamic State fighters were using the storage facility as a logistics hub.