A passenger plane which crashed in a remote Amazon region collided with another aircraft, Brazilian aviation officials have confirmed.
The Boeing 737-800, flying from Manaus to the capital, Brasília, crashed in the Amazon rainforest on Friday.
All 155 passengers and crew are presumed dead after rescuers reported finding bodies but no survivors.
Aviation officials had been investigating the possibility the plane hit a smaller executive jet.
Denise Abreu, director of the National Civil Aviation Agency (ANAC), told reporters on Sunday that a mid-air collision occurred, but did not release any other details.
Earlier, another aviation official said it was "highly probable" that a collision between the two aircrafts caused the crash.
An executive jet made a forced landing with a damaged wing near the crash site on Friday. Everyone on it survived, but its pilot reported seeing a shadow and hearing a noise.
Aviation officials were interviewing the jet’s passengers and crew, while investigators had removed the aircraft’s black box for analysis, another aviation official said.
Rescuers re-started their search of northeast Brazilian state Mato Grosso on Sunday, two days after a Boeing 737-800 from Brazilian airline Gol with 155 people aboard crashed in the hard to reach area.
The search, which began on Saturday at 1:30 p.m. local time, has not yet confirmed a death, the National Civil Aviation Authority told media. If all the 155 die, then it will be Brazil’s worst ever fatal air crash.
Jose Carlos Pereira, president of the Brazilian Airport Infrastructure Company, said the crash scene was a grisly mess, which gives rescuers little hope of finding anyone alive.
"There are only bodies, fragments of bodies, more body parts and nothing else," he told reporters.
Brigadier Antonio Gomes Leite Filho, from the Brazilian Air Force, said that the search would continue until a satisfactory number of bodies had been found, but said that many of the dead were mutilated beyond recognition.
"Until we have a count which matches the number of passengers, the Air Force will remain in the area, searching until the chance of finding a passenger is zero," Leite said.
On Sunday, 11 indigenous people joined the search, which is taking place in dense jungle in the Xingu National Park, a reserve for the Kayapó, who are known for their knowledge of the Amazon jungle.
Also on Sunday, pilots and passengers from the executive jet – a 2002 Legacy manufactured by Brazilian company Embraer – told media that they had not seen the large passenger craft until it was on top of them, but had felt an impact at 5:30 local time on Friday.
Pilots told police that they had been very surprised that the Traffic alert and Collision Avoidance System had not alerted them to the nearby jet. The TCAS safety device – which automatically communicates flight data to nearby aircraft – is standard on modern aircraft.
GOL officials told media that the pilot of the passenger jet, flight 1907 from Manaus to Rio de Janeiro, was a very experienced pilot, having flown 15,000 hours