(CNN) -- A third person -- identified only as a girl -- has died from injuries sustained in last week's crash of Asiana Airlines Flight 214, officials at the San Francisco hospital where she was being treated said Friday.
San Francisco General spokeswoman Rachael Kagan said the "minor girl" had been in critical condition at the Bay Area hospital since last Saturday's incident. The hospital didn't release any information about the girl -- including her name, age or ethnicity -- who died Friday morning, according to Dr. Margaret Knudson, the hospital's chief of surgery.
"It's a very, very sad day today at San Francisco General Hospital," said Dr. Geoffrey Manley, chief of neurosurgery. "We have all done everything we could."
Two other people -- both 16-year-old girls from China -- were reported dead soon after the Boeing 777 crash-landed at San Francisco International Airport.
One of those teenagers was hit on the runway by a fire truck, though it's not clear whether she was already dead when she was struck, San Francisco police spokesman Albie Esparza told CNN on Friday.
At the time, firefighters were using flame retardant that ended up surrounding areas immediately around the plane with foam, Esparza said.
"When the truck repositioned itself to get a better aim of the fuselage, they discovered the body of the victim in the fresh track from the path of the truck," he added.
The foam was thick enough to cover a body, Esparza noted. Moreover, it is difficult for those in the "industrial-size" fire trucks that responded to crash to see things on the ground, the police spokesman said.
"Right now, we are waiting results from the coroner to determine if she died from the crash or the fire engine going over her," the police spokesman said. "And that will be part of our investigations, like any other case, by our hit-and-run and major accidents investigations teams."
Of the passengers and crew on board, 304 people survived -- 123 of whom walked away relatively unscathed and the remainder sent to hospitals.
A handful of them remained hospitalized, including six patients at San Francisco General as of 3 p.m. (6 p.m. ET) Friday. That hospital's figure include two adults in critical condition with spinal cord injuries, abdominal injuries, internal bleeding, road rash and fractures.
Besides the passengers and crew members' physical recovery, San Francisco International Airport is working to get back to normal as well.
The airport was shut down to incoming and departing traffic for several hours after the Asiana crash, which occurred around 11:30 a.m. Saturday. Two of its four runways reopened later that day, though the charred remnants of the downed 777 remained -- a visible reminder of the horror that had unfolded.
Early Friday morning, that airline's fuselage was hauled away on flatbed trucks to a remote section of the airport, said San Francisco International Airport in a press release.
By 5:05 p.m., a Southwest Airlines jet landed on the runway where the crash occurred -- signifying that, for the first time in six days, all four of the airport's runways were operational.
"The tremendous efforts and around-the-clock work of airport staff, government agencies, airline tenants and contractors allowed us to complete all repairs and safety certifications for Runway 28L in a timely and efficient manner," said airport director John L. Martin.
While the wreckage has been hauled away, investigators still have not pinpointed exactly why Flight 214 crashed, or who was to blame.
An in-depth review of the cockpit voice recorder shows two pilots called for the landing to be aborted before the plane hit a seawall and crashed onto the runway, the head of the National Transportation Safety Board said Thursday.
The first internal call by one of the three pilots in the cockpit to abort the landing came three seconds before the crash and a second was made by another pilot 1.5 seconds before impact, NTSB chief Deborah Hersman said.
The agency has begun wrapping up its investigation at the airport and crews are cleaning up the debris left by the crash. Investigators turned the runway back over to the airport. The runway has been closed since Saturday's crash.
The investigation is shifting back to NTSB headquarters in Washington, where authorities will work to find a more definitive answer about what led to the crash.
The passenger jet's main landing gear slammed into the seawall between the airport and San Francisco Bay, spinning the aircraft 360 degrees as it broke into pieces and eventually caught fire.
CNN's Chelsea J. Carter, Augie Martin and Ed Payne contributed to this report.