Meteorite Shower in Russia.

At least 250 people have been injured after a meteor shower over central Russia blew out windows, interior ministry sources say.

Brightly burning rocks could be seen for hundreds of kilometres as they crashed into the Ural region.

Chelyabinsk residents reported shaking ground and car alarms being set off.

The traces from falling objects could be seen in Yekaterinburg, about 200km (125 miles) north of Chelyabinsk, a witness told the Reuters news agency.

At least 100 people - many injured by broken glass from shockwaves caused by the shower - have been taken to hospital for treatment, medical officials in the city have said.

An asteroid as large as an Olympic swimming pool will race past the Earth on Friday at a distance of just 27,700km (17,200mi) - the closest ever predicted for an object of that size.

It will pass closer even than the geosynchronous satellites that orbit the Earth, but there is no risk of impacts or collisions.

A big rescue and clean-up operation involving more than 9,000 workers is going on in the Ural mountains following Friday's meteor strike, Russia's emergencies ministry says.

President Vladimir Putin ordered the operation to help some 1,200 people who were injured, including 200 children, mostly by shattered glass.

The shockwave damaged an estimated 200,000 sq m (50 acres) of windows.

Russian officials put the cost of the damage at about 1bn roubles ($33m).

It weighed about 10 tonnes when it entered the Earth's atmosphere and broke apart 30-50km (20-30 miles) above ground, according to Russia's Academy of Sciences, releasing several kilotons of energy - the equivalent of a small atomic weapon.

However, the US space agency Nasa said the meteor weighed 10,000 tonnes before entering the atmosphere, and released about 500 kilotons of energy. The atomic bomb dropped on Hiroshima in 1945 was 12-15 kilotons.

Scientists have played down suggestions that there is any link between the event in the Urals and 2012 DA14, an asteroid which raced past the Earth later on Friday at a distance of just 27,700km (17,200 miles) - the closest ever for an object of that size.