Divers are scouring the bottom of a Russian lake for fragments of a meteor that plunged to Earth in a fireball and caused a booming shockwave.
Part of the 10-tonne space rock, which sparked terror when it blazed across western Siberia, is believed to have landed in the frozen Lake Chebarkul.
Curious onlookers gathered nearby were stopped from venturing out on to the lake by police as the search continued.
Some 20,000 rescuers and recovery workers have already been dispatched to the region around Chelyabinsk to help stricken residents.
Experts are also examining major buildings in case they have been structurally damaged by the blast.
Workers in Chelyabinsk examine the damage to a large building Around 1,100 people were injured and thousands of homes were damaged in the fallout from the strike in the Urals on Friday morning.
Residents who had poured into the streets to watch the light show after spotting the initial flash were wounded by glass shattered by the subsequent sonic boom.
Windows in more than 4,000 buildings across the region were blown out, sending glass flying.
The authorities have promised to them all fixed within a week but this is a long wait when even midday temperatures are -12C (10F).
Crews from glass companies in other regions are being flown in to help as volunteers and residents cover windows with plastic sheeting and gather warm clothes and food.
Some 15 people are still in hospital following the blast. The regional health ministry said one was in a coma.
The meteor burned brightly in the sky before plunging to Earth Regional governor Mikhail Yurevich said the cost of the damage from the explosion is estimated at 1bn rubles (£21m).
As the recovery mission begins in earnest, the emergencies ministry said six divers would be inspecting the lake for any pieces of meteorite.
Emergencies Minister Vladimir Puchkov added: "We have a special team working ... that is now assessing the seismic stability of buildings. We will be especially careful about switching the gas back on."
Scientists will be desperate to examine the rock for any clues about the cosmos but Mr Puchkov said no fragments had yet been discovered.
The explosion appears to have been one of the most stunning cosmic events over Russia since 1908 when an asteroid was blamed for a massive blast in Siberia.
Nasa estimated that the amount of energy released when the meteorite crashed into the Earth's atmosphere was about 30 times more than the force of the Hiroshima nuclear bomb.
The meteor hit in the Urals on Friday morning "We would expect an event of this magnitude to occur once every 100 years on average," said Paul Chodas of NASA's Near-Earth Object Program Office.
The drama happened just hours before an asteroid whizzed safely past the Earth at an unprecedented distance of 17,200 miles.
This is closer than some distant satellites and set alarm bells ringing in some Russian circles about the need for joint global action to protect Earth from space.
Russian parliament's foreign affairs committee chief Alexei Pushkov wrote on Twitter: "Instead of fighting on Earth, people should be creating a joint system of asteroid defence."
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