Provincial deputy police chief Abdul Wasay Gulbahari told Ariana News that the incident took place at around 4pm this afternoon.
He added that the mortar was detonated at a residential house in Shah Mast Qalandar village in PD3 of the province.
According to Mr. Gulbahari, all of the victims were taken to the main hospital in Charikar City which is the capital of Parwan province.
Afghan security officials have blamed Taliban for the incident.
Civilians especially women and children are the most vulnerable targets to unexploded munitions scattered across the country during nearly two decades of war.