The United Nations Assistance Mission in Afghanistan (UNAMA) says "initial, impartial" findings indicate the Afghan National Army fired mortars on a market in the southern province of Helmand earlier this week, inflicting multiple civilian casualties.
"Multiple credible sources assert that the ANA [Afghan National Army] fired lethal mortars in response to Taliban fire, missing the intended target," UNAMA said in a tweet on June 30.
Afghan officials have said at least 23 civilians were killed and 15 others wounded in the June 29 explosions in Sangin district. Children were among the dead.
The militant group and the government blamed each other for the blasts, with President Ashraf Ghani calling the incident a "terrorist attack."
In a separate tweet, UNAMA urged the warring sides to "stop fighting in civilian-populated areas," saying "such indirect-fire incidents in ground engagements cause 1000s of civilian casualties each year."
The UN mission also called on the Afghan government to set up an independent team to investigate the incident.
Helmand is a volatile province largely controlled by the Taliban.
On June 28, officials said a roadside bomb in the province’s Washer district left six civilians dead, including women and children.
Violence had dropped across much of Afghanistan after the Taliban offered a brief cease-fire to mark the Eid al-Fitr festival last month, but officials say the insurgents have stepped up attacks in recent weeks.