A plane crash-landed at San Francisco International Airport, killing at least two people, injuring dozens and forcing passengers to jump down emergency inflatable slides to safety as flames tore through the jet.
More than 60 passengers were unaccounted for among the 307 passengers and crew aboard the Asiana Airlines Boeing 777, said San Francisco fire chief Joanne Hayes-White. It was not immediately clear where they were, but she said they were not all presumed dead at this time.
"This is a work in progress," she said, adding the investigation has been turned over to the FBI and that terrorism has been ruled out. She said at least 48 people were initially transported from the scene to hospitals.
The Federal Aviation Administration said Flight 214 from Seoul, South Korea, crashed while landing before noon local time. A video clip posted to YouTube showed smoke coming from the jet on the tarmac. Passengers could be seen jumping down the emergency slides.
Television footage showed the top of the fuselage was burned away and the entire tail was gone, with pieces strewn over the runway. One engine appeared to have broken away and emergency responders could be seen walking inside the burned-out wreckage.
It was not immediately clear what happened to the plane as it was landing, but some eyewitnesses said the aircraft seemed to lose control and the tail may have hit the ground. Stephanie Turner told ABC News that she noticed the angle of the plane's approach seemed strange. And jogger Kate Belding said it was approaching the runway in a way that "just didn't look like it was coming in quite right". "Then all of a sudden I saw what looked like a cloud of dirt puffing up and then there was a big bang and it kind of looked like the plane maybe bounced (as it neared the ground)," she said. "I couldn't really tell what happened, but you saw the wings going up and (in) a weird angle."
Airport spokesman Doug Yakel said he did not yet know how many passengers were aboard the flight. "We also don't have any information at this time to the status of those passengers," he said.
San Francisco General Hospital spokeswoman Rachael Kagan said the age of the adult patients ranged from 20 to people in their 40s.
The National Transportation Safety Board said it was sending a team of investigators to San Francisco, headed by NTSB chairman Deborah Hersman. Boeing said it was preparing to provide technical assistance.
US president Barack Obama expressed gratitude to the first responders at the crash scene. Mr Obama has directed his team to stay in constant contact with federal, state and local partners as they investigate and respond to the accident. The White House said the president's thoughts and prayers were with the families of those affected by the crash.