A spokesman for the provincial police department, Abdul Ahad Chopan, said the incident took place early Saturday morning in Marjah district.
Mr. Chopan further added that at least two children were among those injured following the explosion which took place in Qari Sadi area.
Officials in the provincial emergency hospital confirmed that the two children who were injured following the blast were taken to the hospital for treatment.
In the meantime, Gen. Zahir Azimi, spokesman for the ministry of defense of Afghanistan said the incident took place after a civilian vehicle struck an improvised explosive device.
No group including the Taliban militants has so far claimed responsibility behind the incident.
Local officials blame the Taliban militants for the incident as Taliban fighters frequently use improvised explosive device (IED) as the weapon of their choice to target Afghan and coalition security forces which normally lead to civilian casualties.