Provincial Governor Ahmad Farid Baseem said that nearly 60 were wounded in the attack. Public Health Ministry, however, said that the toll of injured rose from 55 to 65.
Nasrat Rahimi, a spokesman for Interior Ministry, said that some of the injured were in life-threatening condition.
The attack involved a suicide car bomb being detonated near the facility, followed by gun battle.
The blast was so heavy that it caused severe damages at the police headquarters and nearby residential homes.
A nearby school was also severely damaged by the bombing, which involved use of a military vehicle.
The attack was one of the deadliest in recent months. It came amid peace talks between the United States and the Taliban.
Some experts criticize intelligence institutions for failing to prevent such attacks.