A group of children set off an unexploded mortar round in a residential area in eastern Afghanistan on Sunday, causing a blast that killed a woman and two children, according to provincial official.
Afghanistan is littered with land mines and unexploded munitions left over from decades of war, which kill and wound hundreds of people every year.
Both the Taliban and an Islamic State affiliate are active in Nangarhar.
The mortar is believed to have been fired by Taliban militants on Saturday, with the deadly explosion occurring Sunday at 7 a.m.
The Taliban has been waging a bitter fight in Afghanistan with the ultimate goal of ruling the country and imposing its strict interpretation of Islamic law. The group controlled Afghanistan until 2001, when it was overthrown by the US-led coalition that invaded the country following the 9/11 attacks.