A Boeing 777 has crashed while landing at San Francisco International Airport. Smoke was seen coming from the plane, with emergency escape chutes deployed and passengers sighted sliding to safety.
Televised pictures showed the plane, an Asiana Airlines passenger aircraft arriving from South Korea, on the runway with a large plume of smoke emerging from it.
People left the plane via emergency chutes that had been deployed on the left side of the aircraft. Firefighters were seen dowsing the flames, with a large hole in the plane's roof.
Local television channels said there were several fatalities, but there was no official confirmation. San Francisco's General Hospital said it was treating eight adults and two children with critical injuries.
Federal Aviation Administration (FAA) spokeswoman Laura Brown said the sequence of events was still unclear, but it appeared the plane - flight number 214 from Seoul - had landed before crashing.
One witness, a plane spotter, told the news network CNN that he heard a pop and an initial large fireball appear below the craft as it landed, after which the plane went out of control. The right wing of the plane appeared to have struck the ground.
Tweet shows escape
The plane was reported to have remained upright, but also to have spun around full circle. A full investigation is to be carried out by the National Transportation Safety Board (NTSB) and the FAA.
One photo posted on Twitter showed people streaming out of the jet. "I just crash landed at SFO. Tail ripped off. Most everyone seems fine. I'm ok," tweeted passenger David Eun.
Whether an emergency landing had been scheduled was initially unclear. However, it is understood there were no emergency vehicles deployed on the runway.
Initial reports said the airport was shut down to traffic, with flights being diverted to Los Angeles.
A tweet from Boeing said. "Our thoughts are with everyone affected by today's incident at SFO. We stand ready to assist the NTSB."
According to the website of South Korean airline Asiana, its Boeing 777 can carry between 246 to 300 passengers. The twin-engine 777-200 is one of the world's most popular long-distance planes, regularly used for flights of 12 hours or more.
rc/ipj (AP, AFP, Reuters, dpa)