The Masquerade club, in the basement of a high-rise building in Istanbul, was closed and being renovated during the day.

The fire broke out just after midday, Istanbul governor Davut Gül said, adding that the cause was unclear.

Mr Gül said that the victims of the fire were thought to have been involved in the renovation work.

Eight people, including the nightclub manager and a person responsible for the renovations, have had warrants out for their arrest in connection with the fire as investigations continue.

Three of them have been detained, while warrants are outstanding for others.

Firefighters and other first responders surrounded the charred and smoking entrance to the club, which occupies two floors underneath a 16-storey residential building in the city's Gayrettepe district.

The number of victims has rapidly increased throughout the afternoon, with the governor's office issuing a string of updates.

The newly re-elected Mayor of Istanbul, Ekrem Imamoglu, said the club had not applied for the correct construction permit.

"There is no application [to the local municipality] for a renovation or a construction regarding the place and as it was two floors down from the ground level, it [the work] wasn't visible," he said.

He also offered his condolences on social media to the victims.

"May God have mercy on our citizens who lost their lives, and I wish a speedy recovery to our injured," he said in a post on X, formerly Twitter.

Turkey's President, Recep Tayyip Erdogan, is aware of the tragedy following a phone call with interior minister Ali Yerlikaya.

bbc