Taliban insurgents killed 15 police on the main highway in western Afghanistan, officials said Thursday, in the latest attack to highlight a recent escalation in rebel strikes as NATO-led troops withdraw. \"A convoy of police who went to inspect a highway patrol unit were caught in a Taliban ambush on Wednesday,\" Farah province spokesman Abdul Rahman Zhuwandi told AFP. \"There was fighting between them in which 15 national police were killed and 10 wounded, while several Taliban were also killed.\"