KARACHI, Pakistan At least three security personnel were killed and six others, including rescuers, were wounded when unidentified gunmen ambushed ambulances in northwestern Pakistan, officials said Monday. Muhammad Asif, a spokesman for emergency service Rescue 1122, told local media outlet Nukta that two ambulances were transporting five injured members of the paramilitary Federal Constabulary when the attackers opened fire in the Karak district of Khyber Pakhtunkhwa province. “Three FC