The snow-covered roof of a Moscow market collapsed on Thursday, killing at least 56 people and trapping others beneath the rubble, said emergency officials.

Rescuers are using pickaxes and metal cutters to clear away the wreckage of the Bauman market, which collapsed around 5 a.m. local time.

Emergency Situations Minister Sergei Shoigu said people could be heard knocking and crying out beneath the rubble. Another Russian official, Emergency Situations Ministry head Yuri Akimov, said some were using cellphones to tell family and friends they were alive.

The devastation following the roof collapse of a Moscow market Thursday. (AP Photo/ Misha Japaridze)
The devastation following the roof collapse of a Moscow market Thursday. (AP Photo/ Misha Japaridze)

Rescue teams piped warm air into the rubble to help survivors deal with freezing temperatures, and say they have no idea how many people were in the market when the roof collapsed.

About 32 people escaped with injuries, said officials.

It's not clear what caused the collapse, but investigators say it could be either heavy snow, substandard building maintenance or improper building design. Up to eight centimetres of snow fell overnight.

Relatives of the some of the victims mourn near the wreckage of the collapsed market in Moscow. (AP Photo/Alexei Sazonov)
Relatives of the some of the victims mourn near the wreckage of the collapsed market in Moscow. (AP Photo/Alexei Sazonov)

Moscow Mayor Yuri Luzhkov has ruled out Chechyn-related terrorism connected to Thursday's state holiday, Defenders of the Fatherland Day, which honours the country's armed forces.

Chechyn rebels fighting for an independent homeland have claimed responsibility for a number of attacks within Russia.

Witnesses say the death toll would have been much higher if the market had been open for retail business. It's believed many of the victims worked at the east-end market.

The collapse comes two years after the roof of a Moscow water park – built by the same architect – collapsed, killing 28 people. The architect, Nodar Kancheli, blamed terrorists.

Kancheli, who was charged with negligence in April 2005 for the water park incident, told a local radio station that the snow had been permitted to build up on the market's roof, according to the by Itar-Tass news agency.