A meteor weighing an estimated 10 tons streaked at supersonic speed over Russia's Ural Mountains, setting off blasts that injured some 500 people and frightened many more.
The meteor over the Chelyabinsk region entered the Earth's atmosphere at a speed of at least 33,000mph and shattered about 18 to 32 miles above ground, the Russian Academy of Sciences said.
The fall caused explosions that broke glass over a wide area. The Emergency Ministry said more than 500 people sought treatment after the blasts and 34 of them were taken to hospital.
"There was panic. People had no idea what was happening. Everyone was going around to people's houses to check if they were OK," said Sergey Hametov, a resident of Chelyabinsk, the biggest city in the affected region, which is about 930 miles east of Moscow.
"We saw a big burst of light then went outside to see what it was and we heard a really loud thundering sound," he said.
Another Chelyabinsk resident, Valya Kazakov, said some elderly women in his neighbourhood started crying out that the world was ending.
People heading to work in Chelyabinsk heard what sounded like an explosion, saw a bright light and then felt a shockwave.
A fireball blazed across the horizon, leaving a long white trail in its wake that could be seen as far as 125 miles away in Yekaterinburg. Car alarms went off, windows shattered and mobile phone networks were interrupted.
"I was driving to work, it was quite dark, but it suddenly became as bright as if it was day," said Viktor Prokofiev, 36, a resident of Yekaterinburg in the Ural Mountains. "I felt like I was blinded by headlights."
No fatalities were reported but President Vladimir Putin and Prime Minister Dmitry Medvedev were informed.
Windows were shattered on Chelyabinsk's central Lenin Street and some of the frames of shop fronts buckled.
A loud noise, resembling an explosion, rang out at around 9.20am. The shockwave could be felt in apartment buildings in the industrial city's centre.
"I was standing at a bus stop, seeing off my girlfriend," said Andrei, a local resident who did not give his second name. "Then there was a flash and I saw a trail of smoke across the sky and felt a shockwave that smashed windows."
A wall was damaged at the Chelyabinsk Zinc Plant, but a spokeswoman said there was no environmental threat.
Meteors typically cause sizeable sonic booms when they enter the atmosphere because they are travelling much faster than the speed of sound, but injuries on the scale reported yesterday are extraordinarily rare.
Reports conflicted on what exactly happened in the clear skies. A spokeswoman for the Emergency Ministry, Irina Rossius, said there was a meteor shower, but another ministry spokeswoman, Elena Smirnikh, was quoted as saying it was a single meteor.
The dramatic events prompted an array of reactions from prominent Russian political figures. Mr Medvedev, speaking at an economic forum in the Siberian city of Krasnoyarsk, said the meteor could be a symbol for the forum, showing that "not only the economy is vulnerable, but the whole planet".
Deputy Prime Minister Dmitry Rogozin said the incident showed the need for leading world powers to develop a system to intercept objects falling from space. "At the moment, neither we nor the Americans have such technologies" to shoot down meteors or asteroids, he said.