A powerful Ukrainian rebel leader has confirmed that pro-Russian separatists had an anti-aircraft missile of the type Washington says was used to shoot down Malaysia Airlines flight MH17 and it could have originated in Russia.

In an interview with Reuters, Alexander Khodakovsky, commander of the Vostok Battalion, acknowledged for the first time since the airliner was brought down in eastern Ukraine on July 17 that the rebels did possess the BUK missile system and said it could have been sent back subsequently to remove proof of its presence.

Before the Malaysian plane was shot down, rebels had boasted of obtaining the BUK missiles, which can shoot down airliners at cruising height. But since the disaster the separatists' main group, the self-proclaimed People's Republic of Donetsk, has repeatedly denied ever having possessed such weapons.