PESHAWAR, Pakistan (AP) — Militants ambushed a police vehicle in restive northwest Pakistan on Wednesday, killing four officers and wounding two others, officials said. The attack occurred in the Dera Ismail Khan district of Khyber Pakhtunkhwa province as officers were heading to a nearby town to conduct an operation aimed at arresting a local Pakistani Taliban commander, senior police official Sajjad Khan said. Police returned fire and an exchange of gunfire was ongoing, he said. The Pakistani