By Will Stewart
Firefighters attend the scene of the Polish air crash: Footage has emerged that claims to show Russian-speaking men shooting survivors
A video of the plane crash which killed the president of Poland apparently shows survivors being shot.
The video, which is being circulated on the internet, has fuelled conspiracy theories about the accident.
It purports to show film of armed Russian-speaking men killing passengers minutes after the crash which killed Lech Kaczynski and dozens of members of the Polish government and military elite.
The grainy, blurred footage - on which sounds like that of gun shots are heard - has been dismissed as a 'malicious hoax' by a Russian aviation expert.
Some Russian sources have claimed the video has been circulated in an attempt to smear Moscow by either Ukrainian or Georgian groups by implying that there may have been a planned operation to down the plane.
The video - which has been digitally manipulated, with subtitles added and certain segments slowed down or zoomed in on - is unclear.
No one is actually seen being shot on the footage. Some internet viewers have pointed out inconsistencies, such as trees moving around.
There has been no official comment from the Moscow prosecutor general's office, which is involved in the crash investigation.
Polish investigators have demanded more protection for the crash site from the Russians, and have secured permission for their own examination of the crash site
Footage from the film appears to show a person jumping from the cockpit after the plane crashed
The official investigation has ruled out foul play as a cause of the crash in dense fog which killed all 96 people on board on April 10.
Until now there has been no suggestion that anyone survived.
Claims include fears that vital Nato secrets and other classified military information fell into the hands of the Russian secret service in the aftermath of the flight and that a mystery woman was in the cockpit seconds before the crash.
Passengers on the doomed Tupolev-154 were on their way to commemorate the anniversary of the Katyn massacre, in which some 22,000 officers were murdered by Soviet secret police in 1940.
Many of the bodies from the crash were badly mutilated and could only be identified by DNA, but no reports have suggested bullet injuries to any of the passengers
The footage - over which gun shots are heard - was dismissed as a 'malicious hoax' by some Russian sources
However, there have been unconfirmed reports that Andrej Sheremet, the Polish general prosecutor, believes the footage to have been made at the crash site in the forest near Smolensk.
Another conspiracy theory claimed that the journalist who either made or held the footage - named in some accounts as Andrei Menderei - was stabbed in the back in the Ukrainian capital of Kiev in the days following the crash.
It is then claimed that he died at a clinic in the city soon afterwards when his artificial respiration machine was turned off by unknown intruders.
Another Russian account suggests that the footage was filmed by someone living close to the crash site - and that later an 'incorrect and sensational interpretation' was put on the film.
According to this theory, the gunshots heard were produced by the guns which were carried by the president's security men, which discharged after being caught in fire.
None of this could be verified last night.
People stand near the wreckage of a Polish government Tupolev Tu-154 aircraft that crashed near Smolensk airport on April 10
Memorial: The coffin of Polish president Lech Kaczynski is laid out at the Presidential Palace chapel in Warsaw, Poland
The Russian aviation expert, who asked not to be named, said last night: 'The use of this footage is a malicious hoax aimed at damaging Russia, nothing more and nothing less.'
The story was seized on yesterday by anti-Russian groups in the former Soviet Union and eastern Europe, and was spreading rapidly across the internet.
Meanwhile, analysis of one of the plane's three black boxes suggests a woman's voice is heard on the flight deck moments before the crash.
Investigators are probing whether a stewardess or a female aide to President Lech Kaczynski was in the cockpit - contrary to regulations - as it went down.
The plane had attempted to land at Smolensk airport in Russia despite receiving clear orders from ground control to fly on to Moscow or Minsk.