Among the detained individuals are a nightclub's managers and several individuals responsible for renovation works, the office noted. It emphasized that a comprehensive investigation into the incident is currently underway, the Istanbul governor's office told Xinhua on Wednesday.

The fire erupted on Tuesday during renovation activities at a nightclub in the basement of a 16-story building in the Gayrettepe neighborhood of the Besiktas district on the European side of the city.

Preliminary findings by firefighters suggested that the fire started when fiber materials ignited during welding, and those inside were trapped by intense flames and smoke, unable to find a way out.

The NTV broadcaster reported that the venue had only one exit, and the majority of casualties were caused by smoke inhalation.

Kazim Beceren, head of the Fire Protection and Education Foundation of Turkey, told the state-run Anadolu Agency that the incident underscores a failure to implement necessary precautions during the renovation phase, particularly concerning fire safety measures.

Beceren said such renovation works should have been conducted under the guidance of occupational safety experts and engineers.

Fire safety expert Levent Yasa said the fire's magnitude was considerable, exacerbated by an abundance of flammable material inside, which tragically resulted in numerous fatalities.

Meanwhile, the Besiktas district municipality emphasized in a statement that "no application had been submitted to the municipality regarding the renovation process and no permission had been provided."

Istanbul's incumbent mayor Ekrem Imamoglu inspected the scene on Tuesday and said municipal teams have been examining the static safety of the building.

"Accordingly, we will support the evacuation of neighbors if necessary. The building is an old structure," he told reporters, speaking of the damage caused by the fire.