The officials further added the incident took place late Tuesday night in Panjwai district.
Provincail governor spokesman Javid Faisal confirming the report said the assailant local police officer poisoned his comrades and then opened fire on his commander.
He said the assailant local police officer managed to flee the area and took some weapons with him.
No group including the Taliban militants has so far claimed responsibility behind the incident.
The threat of insider attacks has become so serious that international soldiers working alongside Afghan security forces are often looked over by so-called guardian angel troops on duty to provide protection.
Foreign troops are not the only targets of such attacks, and the number of Afghan deaths in such incidents is estimated to be at least double the number of ISAF soldiers and trainers killed.
A gunman believed to be an Afghan soldier killed a British service member earlier this month, when he opened fire on ISAF and Afghan soldiers, according to the UK Ministry of Defence.
The “insider” attack occurred on a patrol base in the Nahr-e Saraj district of Helmand province. The victim was part of an engineer’s regiment, MoD spokesman Tom Bennett said in a statement. Six other ISAF soldiers were wounded in the attack, another MoD spokesman said.