The coalition said a review confirmed one strike that day in the area where the casualties were reported. But US officials have not confirmed the senior Iraqi officers account.
Both the Iraqi and US defense departments launched investigations Saturday into possible civilian deaths in airstrikes between March 17 and 23.
While those investigations continue, US Defense Secretary James Mattis said, "There is no military force in the world that is proven more sensitive to civilian casualties."
"We are keenly aware that every battlefield where an enemy hides behind women and children is also a humanitarian field, and we go out of our way to always do everything humanly possible to reduce the loss of life or injury among innocent people," Mattis said. "The same cannot be said for our adversaries."
US and Iraqi forces have been trying to regain control of Mosul -- Iraqs second-largest city -- from ISIS since October.
According to Amnesty International, many of those killed in the airstrikes were "following Iraqi government advice not to leave during the offensive."
"The high civilian toll suggests that coalition forces leading the offensive in Mosul have failed to take adequate precautions to prevent civilian deaths, in flagrant violation of international humanitarian law," said Amnestys Donatella Rovera, who carried out field investigations in Mosul, in a statement.
"The fact that Iraqi authorities repeatedly advised civilians to remain at home instead of fleeing the area, indicates that coalition forces should have known that these strikes were likely to result in a significant numbers of civilian casualties."
Amnesty also accused ISIS forces of "shamefully resort(ing) to using civilians as human shields."