MOSCOW: Scientists said Monday they had discovered fragments of the meteor that spectacularly plunged over Russia's Ural Mountains creating a shockwave that injured 1,200 people and damaged thousands of homes.

The giant piece of space rock streaked over the city of Chelyabinsk in central Russia on Friday with the force of 30 of the nuclear bombs dropped on the Japanese city of Hiroshima during World War II.

It exploded a few dozen miles (kilometres) above Earth but its pieces were widely believed to have scattered over large swathes of the industrial region.

Recovery workers scouring a small lake where at least some of the fragments were believed to have fallen were unable to discover anything in their initial search.

But members of the Russian Academy of Sciences that conducted chemical tests on some unusual rocks on Sunday said the pieces had come from outer space.

"We confirm that the particles of a substance found by our expedition near Lake Chebarkul really do have the composition of a meteorite," RIA Novsosti quoted Russian Academy of Sciences member Viktor Grokhovsky as saying late Sunday.

Grokhovsky's Urals Federal University separately posted a statement on its website on Monday that featured a photograph of a person holding a tiny piece of porous black rock between his index finger and thumb.

"This meteorite belongs to the class of regular chondrites," the university statement said.

Grokhovsky said the rock in question was composed in part of metallic iron as well as chrysolite and sulfite.

Its iron content was estimated at 10 percent.

"Most likely, (the find) will be called Meteorite Chebarkul," the Russian university said.

The meteor's shockwave blew out the windows of nearly 5,000 buildings and left 40 people -- including three children -- recovering in hospital Sunday with cuts and more serious injuries.

About 24,000 emergency workers and volunteers were busy replacing smashed windows over the weekend in time for the resumption of school and work.

But the elusive meteorites -- meteor fragments that have hit Earth -- have generated interest as well.

Russian space debris hunters have posted ads on websites offering as much as 300,000 rubles ($10,000) for an authentic piece of the latest space rock to hit the planet.

Chelyabinsk authorities responded by cordoning off the area around the lake and not allowing any media or independent researchers hunting for meteorites near the hole that developed in its thick sheet of ice.

Grokhovsky said the tiny rock's find and 50 others like it came in the snow not far away from the lake. He also expressed confidence that a much larger meteorite was buried in its waters despite claims from the authorities that it was empty.

The lake "is still cordoned off, but it is quite clear that a meteorite is buried there," the scientist said.

"Since we found the fragments -- traces of the upper layers of the meteorite -- that means that its main mass is resting in the lake," he told the Interfax news agency on Monday.

Grokhovsky added that his research team had not been commissioned by the Russian government but was acting on its own because the event was so rare and required immediate inspection.

"We decided to do this on our own," he told Interfax.

"As a member of the (Russian Academy of Sciences) committee, I simply could not stand idly by. So I decided to send our guys there."