A fire on the roof of the Monte Carlo hotel-casino forced guests and gamblers to flee and sent a plume of smoke above the Las Vegas Strip before easing about an hour later, hotel officials said.
No injuries were reported and firefighters contained the blaze, said Clark County Fire Chief Steve Smith.
"As we go out of the danger zone, we'll methodically check each floor," Smith said. "No rooms are burning."
The fire, which was reported around 11 a.m., halted gambling at the casino as it spread from the center of the building across the roof. Fiery debris fell to the street below, and orange flames lapped at the casino's script sign.
Officials went door-to-door evacuating the 32-story hotel, said Gordon Absher, a spokesman for the resort's owner, MGM Mirage Inc.
Someone yelled 'fire, get out!'
Larry Wappel, 25, of San Pierre, Ind., said he and his brother, Eric Wappel, were in a room on the 30th floor when they heard housekeeping staff banging on doors and yelling "Fire, get out!" He said it took about 10 minutes to walk single-file down the stairs to get to ground level.
"There were a couple of ladies crying, but it was pretty calm," he said.
Another guest, Renza Badilla, 45, said she exited through the hotel kitchen to find burning debris and embers falling from the roof.
"I think people were shocked when they saw the smoke," said Badilla, who said she was in the buffet on the main casino level when fire alarms sounded.
Investigators were trying to determine whether the fire had simply burned the resort's facade or penetrated rooms in the upper floors, which contain suites. Guests were being taken the MGM Grand Garden Arena and employees were evacuated to the adjacent New York-New York hotel, Absher said.
There was no immediate indication of criminal activity or arson, Smith said. He called it an external fire but said heat and smoke set off alarms and sprinklers inside the building.
Foam facade 'melted off'
The facade was made of a foam building material that "melted off the side of the building and started a few fires below," Smith said.
Huge crowds formed to watch the fire, and traffic on the Las Vegas Strip was gridlocked as streets were blocked off around the hotel.
The nearby resorts Bellagio and New York New York were not evacuated.
The Monte Carlo Resort & Casino has 3,002 guest rooms and 211 suites. The resort, located on Las Vegas Boulevard, near Tropicana Avenue, opened in June 1996.
The casino-hotel modeled after the Place du Casino in Monte Carlo, Monaco, was a joint venture between Steve Wynn's Mirage Resorts and Circus Circus Enterprises.