Afghan police officer drugs and kills 10 colleagues
An Afghan policeman, suspected of collaborating with insurgents, drugged and then shot dead 10 of his colleagues in the southern province of Uruzgan, officials say.
He then stole their weapons and set their outpost on fire.
Police are now hunting what they believe to be a Taliban infiltrator.
Insider attacks on international and Afghan forces have been one of the gravest security threats of the later phase of the conflict in Afghanistan.
But the number of such incidents has dropped in recent years after Nato forces adopted special security measures.
More than 100 foreign soldiers and scores of Afghan policemen have been killed in insider attacks.
The Afghan police force is notorious for low morale within its ranks, poor recruitment levels and high desertion rates in the face of a resurgent Taliban.
A small number of police have in recent years also been accused of corruption, kidnapping, drug use, murder and child abuse.
A Taliban spokesman was quoted by the AFP news agency as saying the group carried out Tuesday's attack in the Chinarto district of Uruzgan.
The province borders the Taliban strongholds of Helmand and Kandahar.
Last week four police officers were reported to have shot and killed nine colleagues in Uruzgan before joining the Taliban with weapons and equipment.
The latest violence comes days after Afghan President Ashraf Ghani warned in a BBC interview that if peace talks with the Taliban do not begin by the spring of this year, the conflict could intensify with consequences for the region.
The president said more effort is being made to restart peace talks with the Taliban. They collapsed last year after tentative steps.
The Taliban have stepped up their insurgency despite an acrimonious leadership dispute following the death of their long-time leader Mullah Omar.