MOSCOW (AP) -- The Russian Academy of Sciences is estimating the meteor that streaked into the skies over the Ural Mountains and caused shock waves that injured more than 400 people weighed about 10 tons (11 tons avoirdupois).
The academy said in a statement hours after the Friday morning fall that the meteor entered the Earth's atmosphere at a speed of at least 54,000 kph (33,000 mph) and shattered about 30-50 kilometers (18-32 miles) above ground.
The fall caused explosions that broke glass over a wide area. Interfax says nearly 1,000 people were injured and dozens needed hospitalization.
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, about 1500 kilometers (930 miles) east of Moscow, the biggest city in the affected region.
"We saw a big burst of light then went outside to see what it was and we heard a really loud thundering sound," he told The Associated Press by telephone.
Another Chelyabinsk resident, Valya Kazakov, said some elderly women in his neighborhood started crying out that the world was ending.
Some fragments fell in a reservoir outside the town of Cherbakul, the regional governor's office said, according to the ITAR-Tass news agency. It was not immediately clear if any people were struck by fragments.
The agency also cited military spokesman Yarslavl Roshupkin as saying that a six-meter-wide (20-foot-wide) crater was found in the same area which could be the result of fragments striking the ground.
Meteors typically cause sizeable sonic booms when they enter the atmosphere because they are traveling much faster than the speed of sound. Injuries on the scale reported Friday, however, are extraordinarily rare.
Interior Ministry spokesman Vadim Kolesnikov said that about 600 square meters (6000 square feet) of a roof at a zinc factory had collapsed. There was no immediate clarification of whether the collapse was caused by meteorites or by a shock wave from one of the explosions.
Reports conflicted on what exactly happened in the clear skies. A spokeswoman for the Emergency Ministry, Irina Rossius, told The Associated Press that there was a meteor shower, but another ministry spokeswoman, Elena Smirnikh, was quoted by the Interfax news agency as saying it was a single meteor.
Amateur video broadcast on Russian television showed an object speeding across the sky about 9:20 a.m. local time (0320 GMT), leaving a thick white contrail and an intense flash.
Donald Yeomans, manager of U.S. Near Earth Object Program in California, said he thought the event was probably "an exploding fireball event."
"If the reports of ground damage can be verified, it might suggest an object whose original size was several meters in extent before entering the atmosphere, fragmenting and exploding due to the unequal pressure on the leading side vs. the trailing side (it pancaked and exploded)," Yeoman said in an email to The Associated Press.
"It is far too early to provide estimates of the energy released or provide a reliable estimate of the original size," Yeomans added.
Russian news reports noted that the meteor hit less than a day before the asteroid 2012 DA14 is to make the closest recorded pass of an asteroid -- about 17,150 miles (28,000 kilometers).
But the European Space Agency, in a post on its Twitter account, said its experts had determined there was no connection.
Small pieces of space debris — usually parts of comets or asteroids — that are on a collision course with the Earth are called meteoroids. When meteoroids enter the Earth's atmosphere they are called meteors. Most meteors burn up in the atmosphere, but if they survive the frictional heating and strike the surface of the Earth they are called meteorites.
The dramatic events prompted an array of reactions from prominent Russian political figures. Prime Minister Dmitry 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."
Vladimir Zhirinovsky, the nationalist leader noted for vehement statements, said "It's not meteors falling, it's the test of a new weapon by the Americans," the RIA Novosti news agency reported.
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, according to the Interfax news agency.