Efforts to identify the victims of Brazil's deadliest plane crash that killed an estimated 200 people will take at least 30 days, forensic authorities said.
Most of the bodies recovered from the Sao Paulo wreckage were badly burned as the plane rammed a petrol station and two other buildings after skidding off a wet runway at the city's Congonhas airport on Tuesday night, setting off a huge blaze.
Brazil's attorney general on Wednesday took formal steps to close the controversial Sao Paulo airport until "impeccable security measures are in place and confirmed, and until all doubts are removed."
Brazilian federal justice said on Thursday that the National Civil Aviation Agency (ANAC) and the state firm that manages the country's airports, Infraero, have three days to respond to the attorney general's inquiries and request for Congonhas' closure.
Public prosecutor Marcio Araujo, who filed the complaint, said Congonhas is a "black box."
"Nobody knows what provoked the accident," he said.
The aircraft's flight recorder was found shortly after the crash and sent to the US on Thursday. Brazilian authorities hope an examination by the US National Transportation Safety Board (NTSB) will shed light upon the crash.
But the airport continued to operate, with restrictions on larger aircraft, until a final decision is made. The airport was closed on Tuesday night, but opened again on Wednesday for smaller planes.
Families of the victims are helping with data that may help with the identification of their loved ones. Forensic officials have received 173 bodies and only 13 have so far been identified.
"We cannot talk about deadlines. It is not the deadline that determines the task, sometimes it is the task that gives us the deadline. I think the work to identify all the bodies will last over 30 days," said Carlos Alberto de Souza Coelho, technical director of Sao Paulo's Legal Medicine Institute, as cited by the online edition of Folha de Sao Paulo.
There were 186 on board the Brazilian TAM airliner - arriving from Porto Alegre - and an untold number of people working at a freight deposit and petrol station struck by the aircraft, both of which also caught fire.
According to the latest official figures, 187 people have already been confirmed dead. Of them, 183 bodies were recovered by firemen from the site of the accident and four were rescued alive after the crash but died later in hospital.
Some 80 people - firemen and forensic specialists - are involved in the rescue operations. More than 30 hours after Tuesday night's accident, the freight deposit hit by the plane still threatened to go up in flames, and the risk that it might collapse hampered rescue efforts.
An investigation ordered by Brazilian President Luiz Inacio Lula da Silva continued at the site of the accident. Lula ordered federal police to determine the state of the main runway at Congonhas airport.
The police investigation hopes to determine whether public or private organizations can be held accountable for re-opening the newly resurfaced runway on June 29, before it was fully safe.
Despite the resurfacing, the runway still lacked slashes - known as grooving - meant to facilitate drainage on rainy days and increase the grip of planes at landing to avoid skidding, the president of state airport operator Infraero, Jose Carlos Pereira, said on re-opening. The pending work is scheduled to be undertaken in August.