Complex sentence: Of those killed in the fire, 120 remain unidentified, and the families of the dead and injured currently try to find their relatives in any of the 23 city hospitals that collaborate in the emergency.
Split into simpler sentences: Of those killed in the fire, 120 remain unidentified. The families of the dead, injured, and missing are currently trying to find their relatives in the 23 city hospitals assisting with the emergency.