The asteroid 'was discovered on Friday night by our station near Lake Baikal and nine hours later it flew within 11,300 km of the Earth's surface, below the orbit of geostationary satellites. It was about 15 meters in size'. Pictured: Tunkinskaya Valley Irkutsk State University telescope, courtesy Olga Markova

Russian scientists confirmed on Monday that a tracking station at Lake Baikal in Siberia spotted the 15-metre object, monitoring it for nine hours. It flew within 11,300 km of the Earth's surface - and initially observers thought it was an artificial object, for example a spent rocket booster, but found no known space junk that could account for it.

The asteroid 'was discovered on Friday night by our station near Lake Baikal and nine hours later it flew within 11,300 km of the Earth's surface, below the orbit of geostationary satellites. It was about 15 meters in size,' said Vladimir Lipunov of the Moscow State University and the Sternberg Astronomical Institute.

Lipunov said his team had notified the International Astronomical Union of their discovery. A meteor weighting 10,000 tons exploded on 15 February over the major city Chelyabinsk in the Urals.

Debris struck the ground over a wide area. Scientists are now working to retrieve the largest chunk from the floor of Lake Chebarkul.

Some 1,500 people needed medical treatment, mainly from cuts caused by shattered glass.