An airstrike by security forces killed four people and wounded eight others who were part of a wedding procession in the southeast province of Kandahar, officials said on Friday.
Abdul Raziq, the Kandahar police chief, said Taliban militants had mounted an attack in the Maroof district when security forces responded with an airstrike on Thursday.
"They (Taliban) tried to flee and got mixed up with villagers at a wedding procession. The airstrike killed four civilians, including women and children, and 10 Taliban militants," Raziq told Reuters.
Kandahar province, on the border with Pakistan, is a major center of opium cultivation and a stronghold of the Taliban.
Taliban insurgents often hide in civilian homes after staging attacks on government targets and use civilians as human shields to escape.
Afghan officials said the incident was still being investigated and it was unclear whether the casualties had been caused by Afghan or US aircraft, both of which flew missions in support of the operation.
A NATO spokesman said its aircraft were not involved.
"I can confirm we did not participate in any operations near Ma'ruf (Maroof district) within the past 24 hours," said Col. Knut Peters, a NATO spokesman in Kabul.
According to the United Nations, at least 1,692 civilians have been killed in fighting in the first half of the year.