Malaysia Airlines flight MH17 was brought down by a 'Buk' ground-to-air missile, which exploded near the Boeing's cockpit then peppered the plane with shrapnel, a state-run Russian weapons manufacturer says.

The claim confounds previous Kremlin claims that the flight was shot down by a Ukrainian fighter jet.

Moscow-headquartered Almaz-Antey – which has manufactured Buk missile systems since 2002 – said it conducted its own analysis of the pattern of damage seen on pieces of MH17 wreckage recovered from the fields of eastern Ukraine.

That analysis showed that a Buk-M1 missile exploded 3-4 metres from the plane, close to the left side of the cockpit.