The top three floors of the eight-storey apartment block in the city's Kartal district are reported to have been added illegally, according to Ali Yerlikaya, the Istanbul governor.
At least three people have been found dead in the rubble, and 13 people - including Tekgoz - have been rescued.
At least one fatality has been recorded, while three of at least four people known to be trapped have been rescued.
Murat Kurum, the environment and urbanization minister, told reporters at the scene that some apartments had guests at the time of the collapse, without providing details.
Some residents have been trapped inside the wreckage, but officials haven not provided the exact number of people under the rubble.
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The eight-floor building in which the girl lived collapsed around 4 p.m. local time in the Turkish capital's Kartal district.
Police, ambulances and firefighters raced to the scene in the Kartal district of Turkey's largest city and pulled three people of the rubble.
The chairman for Turkey's Disaster and Emergency Management Authority (AFAD) said search and rescue operations were underway, adding that additional personnel would be requested from neighbouring provinces if necessary.
'We are continuing with our search and rescue efforts so that we can deliver good news (about survivors)'.
This frame made from video shows the site where a seven-story building collapsed, in Istanbul, Wednesday, Feb. 6, 2019.
Yerlikaya also said there was a textile workshop on the ground floor that was operating without a license.