(NBC News) - A huge fireball fell from the skies over Russia's Chelyabinsk region early Friday, resulting in a powerful blast and a spate of dramatic eyewitness videos.
Reports from Russia suggested that the fireball was caused by a meteorite. "Preliminary indications are that it was a meteorite rain," the RIA-Novosti news agency quoted an emergency official as saying. "We have information about a blast at 10,000-meter (32,800-foot) altitude. It is being verified."
Reuters reported that a witness in Chelyabinsk, 930 miles (1,500 kilometers) east of Moscow in Russia's Ural Mountains, heard a huge blast early in the morning and felt a shock wave in a 19-story building in the town center. The sounds of car alarms and breaking windows could be heard in the area, the witness told Reuters, and mobile phones were working intermittently.
The Associated Press quoted a spokesman for the Russian Interior Ministry, Vadim Kolesnikov, as saying that the fireball caused in an explosion and sonic boom that broke windows. He said 102 people called for medical assistance after the incident, mostly for treatment of injuries from broken glass. Kolesnikov also told AP that about 600 square meters (6,460 square feet) of a roof at a zinc factory had collapsed.
Multiple videos posted to YouTube showed the object flaring brightly as it sped across the sky. Twitter users posted photos showing broken windows. One video showed an office building in Chelyabinsk being hurriedly evacuated.
Russian news media quoted local residents as speculating that the blast could have been caused by a missile explosion or a military plane crash, but an unnamed emergency official told Reuters that was not the case. "It was definitely not a plane," the official said, without elaborating. "We are gathering the bits of information and have no data on the casualties so far."
The fireball reports spread just hours before a 150-foot-wide (45-meter-wide) asteroid was due to make a close flyby, coming within 17,200 miles of Earth. It's unlikely that there's any connection between the fireball and the encounter asteroid, known as 2012 DA14. However, a bright flash and explosion in midair would be consistent with the atmospheric entry and breakup of a large meteoroid. If 2012 DA14 were to hit Earth, the scenario might play out in a similar way, but with a far more powerful impact.
In 1908, a massive explosion shook a remote region of Siberia and knocked down millions of trees over an 820-square-mile area. Experts concluded that the blast, known as the Tunguska event, was caused by the midair explosion of a 150-foot-wide asteroid falling to Earth.
Reports suggest that the total figure injured is over 400 with at least three critically injured from broken glass.