Malaysia Airlines flight MH17 was probably brought down over Ukraine by numerous "high-energy objects", an official accident report has said.
Before the report it had been suspected that a ground-to-air missile caused the July 17 crash over a war-torn area of Ukraine in which pro-Russian separatists are fighting.
In a preliminary report into the disaster, which claimed 298 lives, the Dutch Safety Board (DSB) said black box recorders showed there was nothing wrong with the plane before the incident.
Revealing that parts of the wreckage from the Kuala Lumpur-bound Boeing 777 had shown "multiple holes and indentations" the DSB said the debris was "consistent with the damage that would be expected from a large number of high-energy objects that penetrated the aircraft from outside".
Ten Britons were among those who died in the disaster, which came only weeks after another Malaysia Airlines Boeing 777 disappeared over the Indian Ocean.
The DSB said the plane, which had left Amsterdam at 10.31am local time, probably broke up in the air, with aircraft parts, cargo and baggage scattered over an area of about six miles by three miles in eastern Ukraine.
The report said the forward parts of the aircraft probably broke up first and they were found closest to the last recorded position of the aircraft.
The centre and rear parts were found much further east, indicating that they continued in a down and forward trajectory before breaking up.
The plane had been in radio contact with Ukraine air traffic controllers and was flying at a height of 33,000ft when contact was lost at three seconds beyond 1.20pm local time.
The report said: "Damage observed on the forward fuselage and cockpit section of the aircraft appears to indicate that there were impacts from a large number of high-energy objects from outside the aircraft.
"The pattern of damage observed in the forward fuselage and cockpit section of the aircraft was not consistent with the damage that would be expected from any known failure mode of the aircraft, its engines or systems.
"The fact that there were many pieces of aircraft structure distributed over a large area indicated that the aircraft broke up in the air."
Due to the on-going conflict in the area, Dutch investigators have not been able to examine the crash site. But Ukraine air accident investigators were able to take photographs of the wreckage during a number of short visits to the site. Satellite images have also aided the DSB.
DSB chairman Tjibbe Joustra said: "The MH17 crash has shocked the world and raised many questions. The DSB wishes to determine the cause of the crash, for the sake of the loved ones of the victims and for society at large.
"The initial results of the investigation point towards an external cause of the MH17 crash. More research will be necessary to determine the cause with greater precision. The board believes that additional evidence will become available for investigation in the period ahead."
He went on: "The preliminary report issues the first findings in an ongoing investigation.
"From this point on, the investigation team will be working towards producing its final report. The board aims to publish this report within one year of the date of the crash."