RUSSIA: ET may have already contacted humans through messages contained in what is believed to have been a meteorite that hit earth almost 100 years ago, Russian scientists claim.

Quartz boulders found near the site of the Tunguska blast in Siberia, which created a mysterious explosion equivalent to an atomic bomb, appear to contain symbols etched from plasma, according to the Tunguska Phenomenon Research foundation.

The Russian state-funded institute believes there may be messages for humanity from extraterrestrial life forms just waiting to be decoded.

"On the surface of the rocks were strange signs, apparently caused by technological means, possibly with the use of plasma. They were found in the river Podkamennaya Tunguska," said president of the foundation Yuri Lavbin.

Analysis of the boulders showed impurities that do not come from the earth, he said.

While this would fit with the widespread theory that a meteorite had broken up just above the Earth's surface, devastating forests for 2,000 square kilometres, Lavbin takes a different view. He believes that an information container from another galaxy broke up as it was attempting to land on this planet, leaving behind a few fragments. Three years ago, his foundation discovered a 50kg rock which it claims is the first substantial debris from the explosion.

Although scientists from France and Germany want to unravel the meaning of the "messages", Labvin believes Russian experts should have the honour of cracking the codes.

However, the general scientific community has not been impressed with his past findings, which have been dismissed as hoaxes.

The precise cause of the blast remains unclear and could have been caused by an asteroid, a comet's nucleus, or , indeed, an exploding nuclear-powered alien spacecraft.

Although the explosion occurred in a desolate region of Siberia, it created shock waves hundreds of kilometres away.