Unverified reports estimated up to 33 people may have been killed in the strike. Damascus confirmed the reports.
According to the sources, the school that served as a shelter for 50 families from Aleppo, Raqqa and Homs, was almost completely destroyed.
"We haven't completed our assessment of that event yet. But my initial reading is not credible. I think that was a clean strike," Townsend told reporters, noting that the building was used by terrorists.
Last Monday, US Department of Defense spokesperson Capt. Jeff Davis said that the US Central Command was assessing the credibility of civilian casualties reports that appeared after a Thursday US counterterrorism strike in al-Jinah in Syria's Aleppo, which hit a mosque.