Earlier in the day, rescuers pulled a 16-year-old boy out alive from under the rubble two days after the collapse, raising the number of people who have been rescued to 14.
Friends and relatives waited near the wreckage for news of their missing loved ones as emergency teams, aided by sniffer dogs, worked around the clock to reach possible survivors.
Nedim Alemdar said 14 relatives were living in three separate apartments in the building that collapsed in the Kartal district on the Asian side of the city. The building had been the family's home for 25 years, he said.
"We have nine losses. My elder brother, our siblings, our children are all gone," Alemdar, 43, told The Associated Press. "This is beyond imagination."
Three other family members were being treated in the hospital, including his nine-year old son, who was trapped in the rubble for nine hours before he was rescued.
"It was an old building, there were some noises ... we could sense there was something wrong, but we didn't think much of it," he said outside the hospital.
The cause of the collapse is under investigation but a senior Turkish official has said the building's top three floors were added illegally.
Officials have not disclosed how many people are still unaccounted for. The building had 14 apartments with 43 registered residents.
The teenager who was rescued Friday, Mert Aydin, was immediately hospitalized, Interior Minister Suleyman Soylu told reporters. Soylu said he had "breaks and fractures" but was doing well.
The family of another missing woman, Seyma Kambur, received a glimmer of hope Friday.
Relatives told The Associated Press that the 29-year-old's older sister managed to reach Kambur on the phone, while Kambur was still trapped under the rubble along with four others who were still alive.
"Our hopes had almost died but today, a million thanks to God. We're relieved. We'll be even more relieved if we see her face to face," said Nuran Nuroglu, Kambur's cousin.
"She is a very good person . everybody loves her, loves everything about her," said her visibly distraught mother, Nadire Ceri.
Ceri and members of her family were waiting for news at a nearby public school that was turned into a crisis center.
Soylu promised punishment for anyone found responsible for the collapse.