The slain police chief, Sajid Khan Mohmand, was traveling to his office and a traffic jam had slowed his vehicle on a busy narrow road when a suicide bomber riding a motorbike struck it, said eyewitnesses.
A senior police officer was martyred and 11 others -including policemen sustained injuries in terrorist attack at Boghra Road in Chaman, Balochistan.
Three critically injured persons have been sent to Quetta for further treatment.
An emergency has been declared in hospitals and law enforcement and rescue officials have been dispatched to the site of the incident.
Gunfire was also heard in the area following the blast.
He expressed deep grief and sorrow over the loss of precious lives in the attack.
Earlier, the deceased DPO was shifted to hospital after getting severely injured in the blast but he succumbed to his injuries.
The Federal Interior Minister Chaudhary Nisar Ali Khan also strongly condemned the Chaman blast, and sought the report of the incident.
The border crossing between the town of Chaman and Spin Boldak is the second most important crossing on the Afghan-Pakistani border.