Medellin disaster preparedness chief Jaime Enrique Gomez says he still holds out hope of finding all alive following last night's collapse.
He says some 150 people were worked today in rescue efforts in one of the most exclusive neighbourhoods of Medellin, Colombia's second-largest city.
Gomez says officials detected a risk in the 22-story apartment building on Friday and recommended it be evacuated, preventing a greater disaster.