Cairo, Shawwal 22, 1436, Aug 7, 2015, SPA -- Egyptian authorities have stepped up their search for a Croatian man being held by a terrorist ISIS affiliate, with an ultimatum to kill him ending later on Friday, dpa cited unnamed security officials as saying. On Wednesday, the self-styled terrorist ISIS Sinai Province (Wilyat Sina) released a video in which a man who identifies himself as Tomislav Salopek says his captors will kill him unless the government releases Muslim women allegedly held in Egyptian prisons within 48 hours. Security authorities have confirmed the authenticity of the video and the hostage's identity. Police are coordinating with the army in order to determine the whereabouts of the hostage, who works out of Cairo for French oil company CGG. --SPA 12:40 LOCAL TIME 09:40 GMT www.spa.gov.sa/w