A fire broke out on the upper levels of a massive hotel in the heart of Las Vegas on Saturday but there were no immediate reports of injuries, US media reported.
CNN television showed thick black smoke and flames billowing from the roof of the giant 3,000-room Monte Carlo hotel on the Las Vegas Strip.
Television showed the flames appearing to spread across the facade of two wings of the hotel as firefighters on the roof attempted to tackle the blaze. Plumes of smoke could be seen for miles around.
CNN reported that the fire was spreading across the building's synthetic stucco but had not penetrating the interior of the hotel.
Guests at the hotel -- one of the biggest on the Vegas strip -- were being evacuated to neighboring resorts, reports said.
The Monte Carlo, which sits on a sprawling 44-acre site, cost an estimated 344 million dollars to build and opened in 1996.
A fire at Las Vegas' MGM Grand Hotel and Casino in November 1980 left 87 people dead, and nearly 800 injured, the worst disaster in Nevada history.