Four militants were also killed during the attack on Friday in Uruzgan province, which has been plagued in recent weeks by a wave of violent attacks by remnants of the ousted Taliban regime, it said in a statement.
"An air strike on April 29 against an insurgent camp in Uruzgan province resulted in the deaths of four anti-coalition militants and three civilians," the statement added.
Two other children were wounded in the attack and were evacuated by the US military to nearby Kandahar airfield for treatment.
The deaths occurred less than a week after three civilians were wounded in eastern Nangahar province in a clash between militants and US troops.