An Asiana Airlines Boeing 777 crashed while landing at San Francisco International Airport at noon today. According to passengers on the flight and eyewitnesses on the ground, the plane's tail came apart, sending a pillar of black smoke into the air. There were 307 total passengers and crew on board, but so far no word on any casualties. Update: two have been confirmed dead. See notes below.

The flight was Asiana 214, a direct flight from Seoul, South Korea on a Boeing 777-200ER. Passenger David Eun (who also happens to be the VP of Samsung) tweeted from the ground after evacuating:

Other witnesses say the plane's landing gear was down and it was just about to touch down when the tail broke off.

Three alarms were called during the resulting fire. According to Redwood City fire department officials, a few passengers were treated for burns.

Update 1:35 p.m.: As of around Noon, all flights into SFO are being cancelled. Arriving flights were diverted to Oakland and San Jose. Shortly after 1 p.m. the National Transportation Safety Board announced it would dispatch an inspection team to investigate the cause of the crash. It is currently unclear when SFO will reopen.

Update 1:45 p.m.: Other pilots who witnessed the crash from nearby told the Wall Street Journal that the plane "appeared to land unusually hard on the runway—with initial puffs of smoke coming from the landing gear—then cartwheel on the strip and erupt in flames."

Witness Stephanie Turner tells the AP:

"It didn't manage to straighten out before hitting the runway," she said. "So the tail of the plane hit the runway, and it cartwheeled and spun and the tail broke off ... I mean we were sure that we had just seen a lot of people die. It was awful.

"And it looked like the plane had completely broken apart," she said. "There were flames and smoke just billowing."

AviationNYC notes that the landing gear may have touched down early, hitting the rocky shoreline that separates the landing area from the San Francisco Bay:

The aircraft experienced destruction of the landing gear, along with separation of both engines and both the tail and tail cone. The tail section seems to have made contact and separated from the aircraft at rocky shoreline prior to or at the beginning of the runway, far short of the intended touchdown area.

Update, 2 p.m.: KTVU is now reporting at least two dead and 61 others injured in the crash. A dispatcher with the San Francisco Fire Department confirms the numbers. Update: the San Mateo County Coroner officially confirmed two dead around 4:30 p.m. Saturday.

A recording from the air traffic control tower at SFO is currently making the rounds online. It doesn't shed much light on the incident, but it does show how the guys pushing tin are doing a great job of remaining calm and professional in a crisis:

Boeing has also issued a statement on their website: "Boeing extends its concern for the safety of those on board Asiana Airlines Flight 214. Boeing is preparing to provide technical assistance to the National Transportation Safety Board as it investigates the accident."

Update, 2:30 p.m.: More photos from just outside of the evacuated plane are coming from twitterer Eunice Bird Rah, whose father was on the flight:

Update 3:40: The White House released an official statement today, saying, "The President has been made aware of the situation and his team will update him as new information becomes available. We will continue to stay in constant contact with our federal, state, and local partners as they respond to this event."

Stanford confirms it has 5 patients, all of whom suffering minor injures. Mills Peninsula confirms to has admitted 8 (with one in surgery), and St. Francis in San Francisco confirms it is treating 6 crash victims. Most of the injuries were a result of smoke inhalation and/or burns from the fire.

Update 3:45: Plane reportedly did NOT do a cartwheel (as previously reported) after hitting the seawall. According to NBC Bay Area, the plane hit the rock wall, went up in the air, and then came back down hard again.

Update 3:50: More photos of today's crash at SFO.

Asiana Airlines released the following statements:

Update 4:18: At least 40 passengers "badly injured." Also, around 60 people are unaccounted for, SFFD Chief Joanne Hayes-White said during a press conference. There were 291 passengers and 16 crew members on board. 190 of them were evacuated to safety, but 82 of those were hospitalized. Today's crash is being billed as the worst commercial aviation plane crash in SFO's 75 year history.

Update 4:50: San Mateo County coroner confirms two deaths. One body was found near tail of the plane, the other found near the front at near the fuselage. Both are adult females.

Update 5:45 p.m.: Officials are now reporting that only one passenger is still unaccounted for. 123 passengers were treated or released at the airport, 181 went to nine different hospitals across the Bay Area. Two have been confirmed dead. SF General Hospital alone is currently treating 35 patients, including 11 children. Five of those patients are still in critical condition.

Asiana Airlines has released another official statement saying they are "currently investigating the specific cause of the incident as well as any injuries that may have been sustained to passengers as a result" and complying with all associated agencies. The passengers were "77 Korean citizens, 141 Chinese citizens, 61 US citizens, 1 Japanese citizen, etc. for a total of 291 people."

Two out of four runways are currently open at SFO. The next information briefing will come at 7:30 p.m. Saturday evening.

Update 9 p.m.: Around 8 p.m. this evening, San Francisco Mayor Ed Lee said, "this could have been much worse." He also reports that all 307 souls aboard Flight 214 have been accounted for.

Related: Photos Of Asiana Flight 214 Crash At San Francisco International Airport
Video: Passengers Describe Flight 214 Crash Landing At SFO