The meteor struck just as an asteroid known as 2012 DA14, about 46 metres (yards) in diameter, was due to pass closer to Earth - at a distance of 27,520 km (17,100 miles) - than any other known object of its size since scientists began routinely monitoring asteroids about 15 years ago.
(Additional reporting by Gabriela Baczynska in Moscow; Writing by Timothy Heritage and Thomas Grove; Editing by Mark Heinrich)