Search teams recovered a total of seven bodies from the rubble on Thursday, raising the death toll from Wednesday's collapse to 10. 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.
Authorities have not disclosed how many people remain unaccounted-for. The building had 14 apartments with 43 people registered as residents.
"At first I thought a gas tank had exploded in our building. I looked behind me and the building, like a deck of cards, fell to the ground. There were wails, screaming," she said.
Dag added: "People are gone... Just like that disaster during the earthquake, this is the same."
Officials have said the building's top three floors were built illegally although the cause of the collapse is still under investigation.
Experts from the Istanbul branch of the chamber of civil engineers who visited the site concluded that the "load-bearing columns had lost the capacity to carry the weight" of the building, the group said in a statement Thursday.
A majority of buildings in Istanbul are "either unlicensed, illegal or were constructed without any engineering services," the group claimed.
"You don't need to be a civil engineer to guess (the result) of a probable earthquake," the group added.
"Such disasters will continue," the group warned.
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.
"Istanbul is situated on a seismic belt," Akin said. "In the event of an earthquake in Istanbul, we could be faced with a dire picture."
In August, Turkey's emergency management agency, AFAD, warned that up to 30,000 people could be killed in Istanbul if a magnitude-7.5 earthquake were to hit the city of 15 million.
The agency estimated 50,000 people could be critically injured and 44,802 buildings could collapse. Some 2.4 million people would be left homeless.
That warning was made on the anniversary of the Aug. 17, 1999, magnitude-7.4 earthquake that killed more than 17,000 people in northwestern Turkey.
"Provincial authorities are in the process of identifying them and ... action will be taken against buildings that carry risks," he said. "Our citizens' lives and property are of paramount importance."
Suzan Fraser reported from Ankara.