Asiana Airlines flight crashes while landing at San Francisco airport

An Asiana Airlines Boeing 777 with 307 people on board crashed and burst into flames as it landed at San Francisco International Airport on Saturday after a flight from Seoul.

Thick smoke then billowed from the wreckage, and TV footage later showed the fuselage of the aircraft gutted and blackened by fire.

Asiana Airlines said the flight, which had originated in Shanghai, had carried 291 passengers and 16 crew members. Most were Chinese, Korean and US nationals. There were also three Indians on board the plane.

Witnesses said the tail of the plane appeared to hit the approach area of the runway, which juts out into San Francisco Bay, as it came in for landing.

The accident site was covered in white foam used by firefighters, with at least six fire trucks at the scene.

The crash was the first-ever fatal accident involving the Boeing 777, a popular long-range jet that has been in service since 1995. It was the first fatal commercial airline accident in the United States since a regional plane operated by Colgan Air crashed in New York in 2009.

Investigators said they could not yet offer an explanation for the crash. Pictures showed the tail detached from the fuselage, and the landing gear had also sheared off.

The US Federal Bureau of Investigation (FBI) said there was no indication that terrorism was to blame for the crash.

The airport was closed immediately after the incident but two runways later reopened. Some flights were diverted to Los Angeles.

More than 180 people were taken to nine area hospitals, but the majority had relatively minor injuries. As of Saturday evening the number of fatalities stood at two while at least five people were reported in critical condition.

Boeing expressed concern for those on board the flight and added that it will provide technical assistance to the NTSB as it investigates the accident.

A video clip posted to Youtube shows smoke coming from a silver-colored jet on the tarmac.

Passengers could be seen jumping down the inflatable emergency slides. It was not immediately known whether there were any injuries.

A San Francisco airport spokesman said that a component of the facility's instrument landing system that tracks an incoming airplane's glide path has been out of service in recent weeks and was not operational on Saturday.

Seen here, the ground crew watches the crashed plane.

Federal Aviation Administration spokeswoman Laura Brown says the plane was coming from South Korea and was supposed to land on runway 28 left at San Francisco International Airport. She said the sequence of events was still unclear, but it appeared the plane landed and then crashed.

The airline's website says its Boeing 777 can carry between 246 to 300 passengers.

Image tweeted by @LinnJohansen1