At least eight Afghan civilians, including four children, have been killed in an attack in the western Farah Province, Afghan officials says, although it was immediately unclear whether they died in a military air strike or a roadside bomb blast.

Muhammad Naser Mehri, spokesman for the provincial governor, said on March 4 the incident late on March 3 was a roadside bomb explosion that took place in the Bala Buluk district.

But family members of the victims say they were hit by an air strike.

One resident, a 30-year-old mother of four named Salima, said two of her children were killed and a third wounded in an air strike.

Dawlat Waziri, a Defense Ministry spokesman, said an investigation of the incident was under way.

"We are aware of the allegations made by the local people, right now an investigation is going on into the incident in Farah," Waziri said.

At least 22 other people were wounded in the attack, according to local hospital officials.

Farah's Bala Buluk district has been the scene of several recent clashes between Afghan security forces and armed insurgents.

Based on reporting by AP and dpa