Dozens killed as roof collapses at giant market hall in Moscow

President Vladimir Putin has called for "a painstaking investigation" after the concrete and metal roof of a Moscow food market collapsed yesterday, crushing at least 49 people to death.

Rescuers initially thought the roof of the Baumansky market gave way under the weight of snow but investigators said incompetence and negligence could not be ruled out. At least 30 people were injured.

Some survivors were reported to be signalling on their mobile phones or by shouting or tapping as sniffer dogs looked for signs of life and rescuers called for periods of silence. How many people might be trapped was unclear because many of the market traders also slept there.

The early-morning collapse came on a Russian bank holiday so there were few, if any, customers. Survivors talked of a sudden cracking sound before being plunged into darkness. One man, Oktay Salmanov from Azerbaijan, escaped because he was near the main entrance, but he said his three sisters and a colleague had not been so lucky. "I heard a loud noise and fell to the ground and lost consciousness. When I came to I was lying by the entrance. There was smoke and people were screaming." Another man said his brother, who was trapped, had stopped answering his mobile phone.

Most of the dead appeared to be male non-Russian immigrant workers from former Soviet republics such as Azerbaijan and Georgia. Last night, cranes were called in to lift giant slabs of concrete and metal girders, and warm air was being pumped into the wreckage. Relatives checked lists of those in hospital pasted to walls near by. At one point, a man whose hand was protruding from beneath a concrete slab was fed painkillers though an intravenous drip.

Three inches of snow fell overnight and this winter has been one of Russia's coldest for decades with temperatures as low as minus 30C, conditions that can weaken and fracture building superstructures. But investigators are also looking into whether the building was misused, putting undue strain on the roof, or whether its design was dangerously flawed.

The market's architect, Nodar Kancheli, also designed Moscow's Transvaal aqua park, the roof of which collapsed in 2004, killing 28. That tragedy was blamed on a design fault but Mr Kancheli denied he was to blame. He also refused to accept any blame for the market collapse. Snow had not been cleared from the 1970s-era roof, he said, and stall-holders had added kiosks to a mezzanine suspended from the collapsed roof, something he had not envisaged.

There has been a spate of fatal roof collapses across Europe this winter. Sixty-six people died last month when the roof of an exhibition centre in Poland caved in under the weight of snow. The roof of a German skating rink also collapsed, killing more than a dozen people.