Moscow (AFP) - The Russian maker of BUK missiles on Tuesday sought to discredit findings of an official inquiry into the downing of a Malaysia Airlines jet over rebel-held eastern Ukraine last year.

International investigators have concluded after a 15-month probe that Malaysia Airlines flight MH17 was shot down by a Russian-made BUK fired from rebel-held eastern Ukraine, a Dutch paper said Tuesday just hours ahead of the official report.

State-controlled Russian firm Almaz-Antey showed videos of a BUK missile being exploded close to the nose of decommissioned Ilyushin plane.

The experiment, it said, disproved claims the missile was shot down from Snizhne, a village controlled by pro-Russian rebels.

Instead they said the passenger jet seems to have been shot down from territory disputed by insurgents and Ukrainian troops, and by an outdated version of the BUK missile that is no longer in use by the Russian military.

"The results of the experiment completely dispute the conclusions of the Dutch commission about the type of the rocket and the launch site," said Yan Novikov, director of Almaz-Antey, which has been put under Western sanctions.

The firm's glitzy presentation -- which saw reams of slides projected on a giant screen -- was carried live by Russia's state-run media.

It is expected to form a central plank of Moscow's rebuttal to the report from the international inquiry.

"Today we can definitively say that if the Boeing was shot down by a BUK missile system then it was hit by a 9M38 from the area of Zaroshchenske village," company official Mikhail Malyshevsky said.

This older missile is banned from use by Russian military as its expiration date passed in 2011, the company said.

The firm in July suggested the missile could have been the 9M38M1 model, which is a later version of the weapon.

But tests now proved that the earlier type was used, it said on Tuesday.

Other theories floated by Russia over the past year included usage of an air-to-air rocket, possibly Israeli-made, launched by a Ukrainian plane.

All 298 people -- some two-thirds of whom were Dutch -- aboard the doomed Boeing-777 from Amsterdam to Kuala Lumpur were killed when it was blown out of the air over rebel-held east Ukraine on July 17 2014.

Ukraine and its allies in the West have consistently accused rebels for downing the jet with a BUK missile system that was likely supplied by Russia, which Moscow denies.