Update, 11:15 p.m. ET:
Fire officials now say 14 people were transported to a nearby hospital after being injured, mostly while evacuating the plane by sliding down its inflatable chutes, the Associated Press reports.
Two runways were affected by the fire, including one that was closed for 2 1/2 hours, but all have now been cleared to reopen. The National Transportation Safety Board is collecting information about the incident, an agency spokesman told the AP, and Boeing says it's "prepared to provide technical assistance" to the agency.
Jacob Steinberg, a reporter with British newspaper The Guardian, was on the plane and described his experiences:
"A few people started running down the plane from the back, a few people stood up, and the staff were all saying, 'Keep seated,' reassuring people. But I don't think they'd realized what was happening. ... A couple of minutes later the stewards told us to evacuate — that sparked a lot of panic. ... We were kind of laughing and joking afterward. That was the adrenaline kicking in. And now that that's gone we're sort of shaken."
Passengers aboard a British Airways plane were forced to disembark on emergency slides after an engine caught fire. The plane was preparing to take off from McCarran International Airport in Las Vegas.
The Associated Press reports that "billowing black smoke and orange flames could be seen pouring from the plane's wings before about 50 firefighters quickly doused the aircraft."
The 159 passengers and 13 crew members all escaped the plane, McCarran International Airport spokesman Chris Jones said, per the AP.
According to the airport's official Twitter feed, two passengers were taken to the hospital and one runway was shut down.
The airport also tweeted the name and phone number of both the British Consulate in Los Angeles and the British Airways press office in Washington, instructing media to seek information there.
Calls placed by NPR inquiring about the cause of the fire were not immediately returned.
The AP spoke with a woman who witnessed the fire:
"Reggie Buegmuencher, of Philadelphia, said she was charging her phone and waiting at a gate for her flight when she heard people saying, 'Oh, my God.' She looked out the window and could see 'bursts of flames coming out of the middle of the plane.'
" 'Everyone ran to the windows and people were standing on their chairs, looking out, holding their breath with their hands over their mouths,' Buegmuencher said.
"The plane's emergency slides were deployed a few moments later and passengers quickly got off the plane. She said it was a 'bit more orderly' than she would have expected given the dramatic nature of the fire and smoke."