True or not about Spielberg's interest, the lake is perhaps the biggest focus of UFOs in Russia. Picture: othereal.ru

Since ancient times, the vast Lake Baikal has been known as deeply mysterious, but in the closing years of the Soviet era, and since, it has been the location of a number of alleged sightings of aliens and UFOs.

Initially these were covered-up by the authorities of the USSR, but later they were revealed by the Russian media.

In recent days there have been unconfirmed reports in Russia that American director Steven Spielberg is planning a documentary based on these weird and unexplained accounts. At the time of writing, this appeared to be a hoax, though it was unclear who planted stories in the Russian media.

True or not about Spielberg's interest, the lake is perhaps the biggest focus of UFOs in Russia.

The versions of extra-terrestrial activity at Baikal - edged by mountains and containing one-fifth of the world's unfrozen freshwater - relate to supposed aliens seen by military divers in its depth, and large 'spaceships' hovering over its grey, moody expanses.

Some of the images here show what two photographers claimed were UFOs buzzing the lake, while others are mock-ups from NTV based on descriptions of an incident at Kudara-Somon, in Buryatia, exactly a quarter of a century ago.

A number of sightings also indicate bright 'cigar-shaped' objects in the sky flying over Baikal, as in the top picture.

NTV channel mock-up of 'flying saucer' based on accounts by residents of Kudara-Somon village in 1990. Pictures: NTV

A case for which there were no images, but an intriguing description, occurred at Kurma, Irkutsk region, in 17 April 1987. The words that follow are from Valery Rudentsov, a local resident of nearby Shida village:

'There was 13 of us. At about 12.20am, one of our guys went out into the yard, a few seconds later runs, and calls all of us out. He stood in the centre of the yard and pointed his finger at the sky.

'Diagonally from his gesture - 150 metres above us - hung a huge flying saucer. From the centre of the plate went a phosphorescent purple ray. And at the edges of the plate were yellow portholes, almost like in our rural houses. The diameter of the plate was 70 metres. We saw it so clearly and for a long time, someone even suggested he throw a stone at it ...

'The weather was amazingly quiet, no sound was heard from the hanging saucer, although behind us was the village of Kurma - there was the noise of a dog barking, the lowing of cows. We were spellbound.

'It was a full moon and the visibility was so clear that no one of us could doubt the reality of what we saw. And then the plate slid smoothly away, sailed along the shore of the bay and further slipped into the hills of Olkhon. Neither before nor after have I ever met such a thing.

'But since that time it has been a kind of sacrilege to me - not to believe in UFOs. My friend Alexander, a hunter, and his colleagues who lived there for 20 years, often see UFOs - and all is fine, he is still alive. So if to speak about glowing balls or 'cigars', we constantly see these on the shores of Lake Baikal. They exist.'

The case highlighted by NTV channel was on 16 May 1990 in the village of Kudara-Somon, in Kyakhtinsky district, some 300 km from Ulan-Ude, capital of the Republic of Buryatia.

Margarita Tsybikova recalls the UFO's visit to Kudara-Somon. Marina Zimireva shows where the 'flying saucer' landed. Pictures: NTV

Olga Fedorova, a local resident, recalled: 'At some moment everything turned yellow. My daughter came home from school. I looked - her face was yellow.'

The explanation soon became clear, according to accounts from villagers.

Vasily Timofeev spoke of a flying saucer. 'Its diameter was around 30 meters, it shone brightly. But I did not see a clear image of metal or something like this.'

Another resident Margarita Tsybikova said: 'From this dish came down people in shiny, shimmering costumes.' Olga explained: 'There were people, as far as I remember, three people in shining yellow suits. Seems there were people, yes.'

Marina Zimireva, who also says she witnessed this extraordinary sight, said: 'It was some kind of circle, it can be said, it was like a disk. It turned on the edge and and, well, windows were visible.

'I personally decided for myself that they were people. They had some human image. They were the same - straight, slender, they had arms and legs. And their gait was the same as ours. A little lower down there were three in orange suits. They went down from the disk like a man - the steps were very visible.'

Then, as they recounted the strange event, the 'aliens' saw the people watching them. They returned to their spaceship and flew away.

A picture taken by Nikita Tomin, shows three green-shaded lights on a UFO flying above a lakeside resort in Irkutsk region. Pictures: Baikal Press, NTV

Game warden Gennady Lipinsky also recalls seeing a UFO. 'When I saw it, it was flying low. Until it disappeared over the horizon, I kept looking at it. I call it a fireball, and what it really was - I cannot know.'

The chairman of the Union of Photographers of Buryatia, Sergey Konechnykh, Ulan-Ude, was quoted about a much more recent incident, on 9 July 2009, at around 10pm.

'My son and I went out to the balcony, to see the last of the waning sunset. Suddenly there appeared these two glowing points and they hovered over the water.'

His pictures of this incident are clear yet perhaps raise as many questions as they answer. They show two glows in the night sky, featuring a yellow core with an orange-red surround.

By his account, the mysterious crafts rose and rebased elsewhere on Baikal's surface.

Around the same time, Anna Vinogradova, recalled a different but equally strange sight on the water. 'We were standing with tents on the beach and at night we saw orange-red flashes, as if a huge fires,' she said.

At Listvyanka in July 2010, a picture taken by Nikita Tomin, shows three green-shaded lights on a UFO flying above the lakeside resort in Irkutsk region.

The chairman of the Union of Photographers of Buryatia, Sergey Konechnykh shows the pictures he made in July 2009. Pictures: NTV, Sergey Konechnykh

'It flew right above us, very low. The object was shining down on us with a green light. We were a bit scared,' he said.

But the accounts also include 'aliens' in the deep waters of Baikal. Interestingly, unlike several other Siberian lakes, Baikal is not seen as home to a Loch Ness-style monster, but rather boasts space-like aliens under its murky surface.

For example, Vyacheslav Lavretevich, a rescuer, recalled an incident but did not give the date. 'We were on a yacht on Lake Baikal, and from under us flew out a huge glowing disk. It blinded us, and for a second flew into the sky.

'We did not even have time to grab any cameras, nor take video, although many of us saw it. It was a huge - and lit up all of our yacht. In diameter it was probably 500-700 metres, a huge disk.

'For three minutes it shone from below (the surface), and then abruptly departed in a second. The spectacle was huge, awesome. Beautiful, and shocking.'

Vyacheslav Lavretevich, a rescuer, recalled an incident on Baikal. Oleg Chichulin saw strange objects near Cape Svyatoi Nos. Pictures: NTV

Oleg Chichulin was also on a boat, training students. Near Cape Svyatoi Nos they saw strange objects.

'There was a ball that glowed. And then this ball started to fade, fade and blush. And it turned into a red ball. This red ball for a while lay on the water, and then began to sink. And all this gradually, gradually went under the water. And it became dark.'

Yet there are even more intriguing accounts of underwater aliens in the vast lake.

In 1977, when Leonid Brezhnev ruled the Kremlin, two researchers named V Alexandrov and G Seliverstov, were in a submersible device at a depth of 1200 metres in the lake.

The researchers turned off their spotlights, to explore the depth of penetration of sunlight into the water. Suddenly the scientists were bathed in light from an unusual 'glow'.

Aleksandrov recalled: 'It was so like if our device was lit from above and the side by two strong spotlights. Only a minute later, unknown floodlights went out, and we found ourselves in total darkness.'

In 1977 two researchers named V Alexandrov and G Seliverstov, were in a submersible device at a depth of 1200 metres in the lake and observd strange lights. Picture: Vokrug Sveta

In 1982, seven military divers were reported to have come across aliens under the waters of Baikal. Alexey Tivanenko, a doctor of history, said: 'At a depth of 50 metres, they met swimmers, around three metres tall, dressed in tight-fitting silvery suits. They did not have any scuba or other devices, just helmets on their heads.

'They received an order to catch the Ihtiander (half-boy, half-shark, from modern Russian folklore) - but they were immediately washed ashore with signs of decompression.

'They had two decompression devices, but one was broken. All seven people could not be put inside, so they put only four of them. And those three people, who were not put in the device, died on the beach.'

Tivanenko has likened the descriptions to ancient petroglyphs seen by some as being aliens visiting Earth. 'I have hundreds of drawings with these 'Sons of the Sky',' he told NTV.

'They are united by the fact that all of them are tall, dressed in suits, all with the helmets on their heads. And there are mechanisms used by astronauts today.'

'I have hundreds of drawings with these 'Sons of the Sky', told Alexey Tivanenko. Pictures: NTV

Reports surfaced several days ago in the Russian media that Spielberg was expected at Baikal in May, and that he intends to make a documentary entitled Depth 211.

Citing the 'press service' of MUFON - the Mutual UFO Network, a US-based organisation that investigates UFO sightings - news source infobaikal.ru and others reported his trip.

Yet there was no confirmation from the Hollywood director, who has made such films as Close Encounters of the Third Kind and E.T. the Extra-Terrestrial, would be arriving, nor further detail on the reported project.

Later, Komsomolskaya Pravda and IA Teleinform denied the reports but without quoting any sources close to the director.