Dutch experts say Malaysia Airlines flight MH17 broke up in mid-air after being hit by “objects” that “pierced the plane at high velocity” in July.
The new report also said there was “no evidence of technical or human error”.
Correspondents say this matches claims that MH17 was hit by missile shrapnel.
Investigators relied on cockpit data, air traffic control and images, as the crash site in eastern Ukraine remains too dangerous to access amid fighting between government troops and rebels.
The plane was flying from Amsterdam to Kuala Lumpur when it crashed in rebel-held territory in eastern Ukraine.
All 298 people on board, most of them from the Netherlands, died when the plane came down, amid reports it was shot down by pro-Russian rebels.
The report made no comment who might have fired the missile.
Both sides in this conflict use the same weapon, reports the BBC’s transport correspondent Richard Westcott, and to find out who was responsible investigators would need to determine where the missile was launched.
One expert said they should eventually be able to work that out with a combination of radar data and evidence from the scene, our correspondent reports.
A sobering fact highlighted in this report was that three other, very large commercial airliners flew over the same area at around the same time, he adds.
The report from Dutch experts says the plane “broke up in the air probably as the result of structural damage caused by a large number of high-velocity objects that penetrated the aircraft from outside”.
The investigators have not visited the crash site because of fighting in the area but they said photographic evidence of the wreckage suggests the plane split into pieces during “an in-flight break up”.
Maintenance history showed the aircraft was airworthy and had no known technical problems when it took off from Amsterdam, the report added.
Experts said it was manned by “a qualified and experienced crew” and that engines were running normally at 293 knots at 33,000ft (cruise altitude).
Radio communications between the pilot and Ukrainian air traffic control confirm that no emergency call was made.
Criminal investigation
While it is not the final report into the crash, the findings are significant because they are the first official account of what happened, says the BBC’s Anna Holligan in the Netherlands.
A separate criminal investigation is being conducted by prosecutors in The Hague, she adds.
Barry Sweeney, whose son Liam died on board flight MH17, told the BBC the report had given his family some answers as to what happened and had provided some comfort.
Malaysian Prime Minister Najib Razak welcomed the report, saying it “leads to the strong suspicion that a surface-to-air missile brought MH17 down”.
Meanwhile, the rebel leader of the self-proclaimed Donetsk People’s Republic, Aleksandr Zakharchenko, told the Russian Interfax news agency that the separatists did not have the capability to shoot down the plane.
Ukraine’s government and several Western leaders say there is strong evidence that pro-Russian separatists shot down the plane with an anti-aircraft system known as Buk.
Russia has consistently denied allegations that it had supplied any missiles or weapons to the rebels.
The search for evidence has been hampered by heavy fighting in the region, and Malaysian Transport Minister Liow Tiong Lai called on both sides to grant investigators full access.
More than 2,600 people have been killed and thousands more wounded since violence between rebels and Ukrainian government forces erupted in April.
Source: BBC