Article published on the 2008-08-08 Latest update 2008-08-08 14:21 TU
In a statement following the incident, the US army said that the troops were threatened by armed fighters as they approached a compound in central Ghazni province, and responded with gunfire, inadvertently killing the women and child nearby.
The statement added that several militants were killed and another three arrested.
"The coalition regrets the death of these non-combatants," spokesperson Lieutenant Colonel Rumi Nielson-Green said in the statement. "We are planning to conduct a full and thorough investigation."
The incident is one of several of its kind in recent weeks. On 27 July Canadian soldiers from the Nato International Security Assistance Force (Isaf) killed two children when firing on a car which refused to slow down near a patrol in the southern province of Kandahar.
The previous day, Isaf troops had killed four civilians in neighbouring Helmand.
Last month, coalition forces killed eight civilians in an air strike against militants in the southwestern province of Farah. Both Isaf and the coalition are investigating offcial Afghan reports that 64 civilians were killed in two strikes in north-eastern Afghanistan in July.
The United Nations said in June that almost 700 civilians had been killed in Afghanistan this year, of whom about 250 died in military operations while the rest were killed in rebel attacks.
The death toll of military personnel is also on the rise, with the past three months being the deadliest since 2001. More international troops were killed in Afghanistan during this time than in Iraq.