An Afghan woman wearing a police uniform today shot dead a civilian contractor working for Western forces in the police chief's compound in Kabul, NATO said.
It appeared to be the first time that a woman member of Afghanistan's security forces carried out such an attack.
There were conflicting reports about the victim.
A spokesman for the NATO-led International Security Assistance Force (ISAF) said a US police adviser was killed by an Afghan policewoman. Then ISAF said in a statement only that it was a "contracted civilian employee" who was killed.
Mohammad Zahir, head of the police criminal investigation department, described the incident as an "insider attack" in which Afghan forces turn their weapons on Western troops they are supposed to be working with.
After more than 10 years of war, militants are capable of striking Western targets in the heart of the capital, and foreign forces worry that Afghan police and military forces they are supposed to work with can suddenly turn on them.
The policewoman approached her victim as he was walking in the heavily guarded police chief's compound in a bustling area of Kabul. She then drew a pistol and shot him once, a senior police official said.
The police complex is close to the Interior Ministry where in February, two American officers were shot dead at close range at a time anger gripped the country over the burning of copies of the Muslim holy book at a NATO base.
"She is now under interrogation. She is crying and saying 'what have I done'," said the official, of the police officer who worked in a section of the Interior Ministry responsible for gender awareness issues.
Reuters