ISTANBUL (AP) — A fire at an Istanbul nightclub during renovations on Tuesday killed at least 29 people, officials and reports said. Several people, including managers of the club, were detained for questioning.

At least one person was being treated at a hospital, the Istanbul governor’s office said in a statement.

The Masquerade nightclub, which was closed for renovations, was on the ground and basement floors of a 16-story residential building in the Besiktas district on the European side of the city bisected by the Bosphorus. The fire was extinguished.

Gov. Davut Gul told reporters at the scene that the cause of the fire was under investigation and the victims were believed to be involved in the renovation work.

Some of the victims died in hospitals where they were rushed in ambulances, private NTV television reported.

Authorities detained six people for questioning, including managers of the club and one person in charge of the renovations, Gul’s office said.

The nightclub was closed for the holy Muslim month of Ramadan and its owners were trying to complete the renovation work in time for next week’s Eid holiday, which follows the month of fasting, NTV reported.

Police sealed off the area while power and natural gas to the neighborhood was cut off as a safety precaution.

Mayor Ekrem Imamoglu said authorities were inspecting the entire building to assess its safety.

Several firefighting and medical teams were dispatched to the scene, he said.

The nightclub had not obtained the necessary permit to undertake construction and renovations, the mayor said.