gunmen. they re now demanding a half million in ransom. authorities in uganda tonight with a new warning, given what s happened to this american woman. abc s senior foreign correspondent ian pannell has just arrived in uganda for us. reporter: tonight, ugandan officials expanding the search zone as they frantically look for an american woman and her local driver, kidnapped while on a ugandan safari, similar to these promoted by the tour company. a joint operation by police, armed forces and wildlife authorities now looking beyond the queen elizabeth national park, where kimberly sue endicott, identified by neighbors as this woman, and jean-paul mirenge remezo were taken at gunpoint over two days ago. they were with an elderly canadian couple who were allowed to escape and warn authorities. an official in washington telling abc news, it appears the abduction is motivated by money. but there are fears it could ve been poachers or even militia