Local officials in Zabul province said the headless bodies of four men, two women and one child, who were kidnapped by armed men in October from neighbouring Ghazni province, were found in Khak-i-Afghan district of troubled Zabul on Sunday.
The circumstances surrounding the beheadings are unclear. Some local officials pointed the finger at fighters from the Islamic State group (ISIS) in the province, but the government does not have control of the area and the claim could not be independently verified.
Groups associated with ISIS have made growing inroads in Afghanistan this year, attracting fighters and support away from disenchanted members of the Taliban.
“The heartless killing of innocent individuals, especially women and children, has no justification in any religion or creed,” Ghani said in a statement.
Ghani, who was “profoundly saddened” by the killing, said he would convene “an extraordinary security meeting to seek ways for tracking down and punishing the perpetrators of this atrocious crime” later on Monday.
The US also issued a statement condemning “yesterday’s beheading of seven civilians, including women and a child” through its embassy in Kabul.
Also on Monday Afghan officials said heavy fighting continued between militants from the two groups of Taliban in at least three districts of Zabul province.
The skirmishes, which first erupted on Saturday, involved fighters loyal to the widely-recognised Taliban leader Mullah Akhtar Mansour and fighters led by Mansoor Dadullah.
Dadullah is a deputy in the splinter group announced last week by Mohamed Rasool, in the first formal split within the Taliban since the death of long-term leader Mullah Omar.
Islam Gul Seyal, the provincial governor’s spokesman, said the fighting in Arghandab, Khak-Afghan and Daichopan districts continued Monday, and had left dozens of militants from both sides killed and injured. The extent of the fighting and more precise figures could not be verified.