Ukraine says a terrorist act caused flight MH17 to crash en route to Kuala Lumpur, and that it was hit by a missile fired from a Russian-built Buk launcher.
The plane was flying at 10,000 metres when it was hit, according to reports.
Only sophisticated missiles fired either from the ground or from fighter aircraft could reach a target of this height.
The Buk, also called SA-11 or SA-17, is a large ground-to-air missile that can reach a maximum altitude between 11,000 and 25,000 metres depending on the version.
Guided by a radar station on the ground, it would be powerful enough to bring down a large aircraft with a single hit, but not accurate enough to discern between a civilian airliner and a military transport aircraft, experts say.
This type of missile is known to be operated by both the Russian and Ukrainia armed forces, the International Business Times reported.
Larry Johnson, a former CIA official with counterterrorism experience, told Associated Press that if the rebels have a Buk system it is entirely possible that they could have mistaken the civilian airliner for a military transport aircraft before they fired a missile.
"The Buk uses a radar acquisition system for targeting," he said. "These aren't highly trained FAA air traffic controllers. You're tracking something on radar, you see a dot, you get confused. I don't think it was deliberate. I think it was mistaken identity."
He said the Buk is a sophisticated, difficult to operate system used by both the Russian and Ukrainian government military.
Defence experts believe Ukrainian government forces may have abandoned Buk systems when retreating from the area, giving the rebels the hardware, or, they could have been provided by the Russian government, although analysts have said there’s no proof of such a transfer.
In his Facebook update, the Ukrainian interior ministry official said the missile used had been given to separatists by Russia, but that could not be confirmed.
The Associated Press reported seeing the weapon - which resembles a launcher mounted on top of a tank - in the eastern Ukrainian town of Snizhne earlier on Thursday.
Justin Bronk, with the Royal United Services Institute, told AP he believes that if a Buk SA-11 system was used, he is "almost certain" it was supplied by Russia.
"My personal hunch is that given the military setbacks that the separatists have suffered of late, and the Ukrainian military's increasingly confident use of airpower, Russian authorities decided to send a few SA-11 systems across into the Donetsk area," he said.
"However, I also highly suspect that the separatists did not intend to shoot down an airliner, but probably thought they were targeting a Ukrainian transport at high altitude, he said.
The sophisticated missile was developed in 1979 in by the former Soviet Union to intercept other missiles, aircraft and smartbombs.
- AP, Stuff.co.nz