Fire kills 29 at Istanbul nightclub during renovations

At least 29 people have been killed when a fire engulfed Istanbul's underground Masquerade nightclub during daytime renovation work, Turkish local authorities say, prompting dozens of residents living above it to flee.

Firefighters doused the charred and smoking entrance to the club, which occupies two basement floors, as paramedics rushed victims into ambulances.

Earlier footage showed flames reaching the third of the residential building's 16 storeys.

The blaze broke out at 12.47pm in the city's Gayrettepe district, and six people were detained as part of an investigation, the city governor's office said.

Istanbul Mayor Ekrem Imamoglu, re-elected in Sunday elections, told reporters outside the building that there was no application to renovate or do construction at the site, adding that any work would not have been visible from street level.

The Masquerade website said it would be closed from March 10 to April 10 "due to our new design renovation".

It can host up to 4000 people with DJ performances and stage shows several times a week, it says.

A club representative could not immediately be reached.

Authorities cut power, water and gas to the area and building residents were relocated as a precaution.