Thirteen people were pulled out of the debris with injuries, including a 5-year-old girl who was rescued on Thursday, 18 hours after the collapse of the building in the mostly residential Kartal district, on the Asian side of the city.
The block, which was located in the Turkish city's Kartal district, was home to at least 43 people.
An eight-storey apartment building collapsed in Istanbul on Wednesday.
The building, constructed in 1992, had only been granted planning permission for five storeys, he said, meaning the top three storeys were added on illegally.
Some residents have been trapped inside the wreckage, but officials haven not provided the exact number of people under the rubble.
Rescuers carry an injured woman on a stretcher from the site of a collapsed building in Turkey, Feb. 7, 2019.
Can Akin, of the Chamber of Geology Engineers, told The Associated Press that many buildings in Istanbul were built without an adequate investigation of the ground conditions.More news: Asian stocks fall after Trump says no plans for Xi meeting
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The death toll from the collapse has risen to three, with 12 others injured, the Istanbul governor's office announced on Thursday.
Emergency teams pulled at least three people out alive as crowds surrounded the site.
Istanbul Gov. Ali Yerlikaya said Thursday the search for survivors would continue "uninterrupted".
Surveillance camera footage of the moment of collapse which was shown on Turkish television showed people fleeing in terror as the building disintegrated, leaving a huge cloud of dust.
A textile workshop on the building's lower floor was empty at the time, local official Zeki Dag told local media earlier.
Authorities evacuated seven surrounding buildings, and one was under serious risk of collapse.