A large meteorite is thought to have smashed into a forest in a remote area of Russia.
Residents in the town of Bodaibo, in the Irkutsk region of Siberia, saw a large luminous body fall from the sky.
They say the impact caused the ground to shake and made a sound like thunder.
Flashes of bright light could be seen above the impact site, which was a long way from any settlements according to the Russian newspaper Pravda.
"Locals felt a strong shock, which could be comparable to an earthquake," said the report. "In addition to that, the people also heard a thunder-like sound."
Asteroid expert Dr Benny Peiser, from Liverpool John Moore's University, said: "If the eyewitness accounts are confirmed, this fact of an earth tremor together with thunder-like explosive sounds would indicate a rather significant impact event."
He said the incident occurred on the same day as the US House of Representatives debated the need to search for smaller asteroids and the danger of mistaking impacts for nuclear attacks.
At least 30 times a year, asteroids smash into the Earth's atmosphere and explode with the force of a nuclear bomb.
These smaller asteroids, between 200 and 500 metres wide, could potentially demolish a city with a direct hit or cause tsunamis - giant waves - capable of wiping out entire coastal areas if they land in the ocean.
Astronomers estimate there could be between 900 and 1,300 large asteroids measuring one kilometre or more in our part of the solar system, while the number of smaller bodies could amount to 50,000.