Russian divers Wednesday pulled from a murky lake in the Urals a half-tonne suspected meteorite said to have been part of a meteor whose ground-shaking shockwave hurt 1,200 people in February.

The dramatic recovery operation came eight months after a piercing streak of light lit up the morning sky in the central Russian region of Chelyabinsk in scenes some locals said made them think of the onset of a nuclear war.

The meteor broke up into myriad pieces -- some no bigger than the size of a fingernail -- that scientists are still finding across the remote region to this day.

Much of the debris landed in a local lake called Chebarkul that the divers entered on Wednesday in an operation covered live on national television.

Broadcasts showed a team pull out a 1.5-metre-long (five-foot-long) rock from the lake after first wrapping it in a special casing while it was still underwater.

The boulder was then pulled ashore and placed on top of a massive scale for the all-important weighing -- an operation that quickly went partially wrong.

The rock crumbled into several chunks as scientists began lifting it from the ground with the help of levers and ropes.

The scale itself broke the moment it hit the 570-kilogramme (1,255-pound) mark.

"The rock had a fracture when we found it," one unnamed scientist told the lifenews.ru website in a live broadcast.

"It weighed 570 kilogrammes before the pieces fell off. And then the scale broke," said the scientist.

"We think the whole thing weighs more than 600 kilogrammes," he said.

Experts warned it will take time before scientists can certify that the rock they pulled from the lake did indeed come from outer space.

The Vesti 24 rolling news channel reported that divers had already recovered more than 12 pieces from Lake Chebarkul since the February 15 incident.

Only four or five of the pieces turned out to be real meteorites, the channel said.

But researchers at a local university seemed confident in their latest find.

"Based on our initial observations... this is a part of the Chelyabinsk meteor," Sergei Zamozdra, a lecturer at Chelyabinsk State University, told the Interfax news agency.

"This is the largest fragment of that meteor," said the scientist.

"And most likely, it will be one of the 10 largest meteorites ever found."

The meteor weighed a whopping 10,000 tonnes when it exploded a few kilometres up in the air with the force equivalent to 30 of the nuclear bombs dropped on the Japanese city of Hiroshima during World War II.

US scientists said an object that large usually approaches Earth only once every four decades.

Residents of Chelyabinsk -- once a part of the Soviet Union's industrial heartland that has seen a dramatic slide in living standards of late -- have been trying to use the meteor as a way to draw tourists to their isolated part of Russia.

A special council made up of scientists and prominent residents this week urged the local government to erect a six-storey-tall statue in honour of the space rock.

Chelyabinsk media reports said the council is also hoping to set up special hiking trails for foreign tourists interested in visiting the lake and other spots where debris was found.