Fire crews were battling a blaze at the soon-to-be open Fontainebleau Las Vegas hotel and casino late Saturday afternoon.

Thick plumes of black smoke could be seen billowing from the roof of the towering 67-story blue glass property, aerial footage from FOX5 helicopters showed.

It wasn’t immediately clear what sparked the fire or the extent any potential damage at the under-construction property.

Clark County and Las Vegas fire crews were both on scene.

The property is scheduled to open its doors in December after sitting dormant at the north end of the Las Vegas strip for close to two decades.

Construction on the Fontainebleau Las Vegas began back in 2007 and had initially been slated to open in late 2009.

Work stopped, however, when they company went bankrupt during the recession — stalling the project for years.

This is a developing story.