Smokes billows from a fire on the outside pool area of the Cosmopolitan Las Vegas hotel-casino in Las Vegas. The fire on the pool deck of the hotel and casino caused evacuations and the cause of the fire has not been determined. Source: Courtney Cyr via AP Source: AP

The rooftop space erupted into flames about 12.40pm local time — with Clark County Fire Department teams having to scale the building’s 14 storeys to tackle the blaze.

The casino was evacuated as smoke filled the upper floors, setting off fire alarms and setting many patrons to respond in panic.

Firefighters reported finding rooftop trees, landscaping and pool furniture well alight — but that the fire had not taken hold in the building’s structure itself.

Thick black smoke erupted from the casino, startling occupants of nearby high-rise buildings as it billowed through the city’s iconic Strip.

Some 35 fire units and 100 firefighters responded to the call. Las Vegas Boulevard was closed for about 45 minutes. It took firefighters about 35 minutes to extinguish the blaze.

Clark County Fire Chief Greg Cassell told Fox 5 that firefighters will stay on the scene for at least six hours to ensure there is no fresh flare-up.

“Once it got going, it jumped from tree to tree,” he said.

He said the two people hurt during the fire had suffered only minor injuries. One was taken to hospital for observation after smoke inhalation, the other was treated by paramedics at the scene.

A witness told the Las Vegas Sun that the fire may have started in the Bamboo Pool area when a cigarette was tossed into a bush on the pool deck.

Some of the casino’s upper hotel rooms sustained some water damage from automatic sprinkler systems, the fire chief said.

Show stopper ... In this photo provided by Julio Loredo, smokes billows from a fire on the outside pool area of the Cosmopolitan Las Vegas hotel-casino. Source: Julio Loredo via AP Source: AP