Four Afghan police officers have been shot dead and three others have been hospitalized after being attacked by a colleague.
The incident happened at a checkpoint in the Spin Boldak district of Kandahar Province.
Kandahar provincial spokesman Jawid Faysal confirmed the incident and said the three police officers being treated were poisoned.
Police are investigating whether the attacker, who fled, had any links with the Taliban.
It is the latest in a series of insider attacks by Afghan security forces on their local and foreign colleagues.
More that 50 foreign servicemen and dozens of local police officers and soldiers have been killed by insider attacks in this year.
Based on reporting by AFP and RFE/RL's Radio Free Afghanistan