He said the government would take "determined" steps after investigators complete their work and called for speedy urban renewal.
President Erdogan also visited a hospital to talk to survivors, before attending the funeral of the nine members of one family who lost their lives in the disaster. By Saturday, Interior Minister Suleyman Soylu increased the death toll to 18.
"Those who are responsible will be held to account", Soylu said.More news: Anderson Silva, 43, impresses in unanimous decision loss to Israel Adesanya
After the prosecutor's office said it was looking into the cause of the incident, Turkish television stations immediately ended their live broadcasts from the scene.
Turkish media said three of the eight floors had been illegally built - a common practice in the metropolis of around 15 million people.More news: 'Aladdin': A Different Look At Will Smith's Blue Genie Released
Rescue workers remain at the site and it is unclear how many more people are missing.
Instanbul - The number of people confirmed dead after a multistory residential building collapsed in Istanbul has climbed to 16, Turkish state news agency Anadolu reported Saturday.
The collapse fanned criticism of a government amnesty granted past year to people accused of an illegal building - a measure announced ahead of municipal elections this March.More news: Greater metro area sees 3 to 6.5 inches — Sunday snow totals
There were 14 apartments and a total of 43 residents in the building, which was originally built 27 years ago. Seven of them are in serious condition.