Officials had said 59 people were feared missing before the three bodies were found.
Distraught families have been waiting anxiously near the site for news of their loved ones.
Investigations into the cause of the collapse are continuing but initial signs pointed to substandard construction, experts have said.
The rescue operation is complex because vibrations happening in one place can affect other areas, officials say.
But the families of the missing agreed on Thursday for heavy equipment to be used.
At least one crane was deployed to clear the rubble, with more expected to be called upon to speed up recovery efforts after the 72-hour “golden period” for the best chance of survival came to an end.
The rescue operation was complicated by an earthquake that struck overnight on Tuesday, briefly halting the search.
-Agence France-Presse