An Asiana Airlines passenger jet carrying more than 300 passengers and crew crash landed at the international airport in San Francisco, California Saturday.
Flight 214 originated in Seoul, South Korea.
The number of casualties is unclear. But San Francisco General Hospital says it is treating 10 passengers who are in critical condition.
Television pictures show the Boeing 777 on the ground with its tail missing and one wing appearing to have collapsed. The top of the fuselage is burned through. Debris from what appears to be part of the tail is scattered along the runway.
Witnesses say the plane approached the runway at an awkward angle and that, upon landing, it wobbled and spun around, its tail breaking off.
Investigators from the U.S. National Transportation Safety Board are on their way to the scene. They say they plan to work with their Korean counterparts and officials from Boeing as the investigation unfolds.
They hope the flight data recorders will give them vital information into what caused the crash.