A fire at a market warehouse on Moscow's outskirts killed 17 migrant workers Tuesday, Russian media reported.

The victims were workers from Tajikistan and other former Soviet Union states in central Asia, according to a Reuters report.

Fire broke out at the Kachalovsky market at 5 am. The victims were sleeping in makeshift metal sheds attached to the walls of the two-storey warehouse and they couldn't escape from the sheds.   Fire ripped through the metal sheds and roof collapsed during the fire, according to a globeandmail.com report.

The building at the construction materials market was used as a metal storage warehouse.

The cause of the fire was not yet known and investigators indicated the possibility that the fire might have started from electric heaters.

The bodies of the victims were burnt badly, making their identification difficult. The bodies are being identified, but this is difficult as they are all badly burnt, a Moscow migration service spokesperson said, according to a Ria Novosti report.

The death toll is expected to rise further. According to unofficial reports, the workers were living in cramped conditions and the shed did not have a direct exit to the street that prevented them from escaping during the fire, Ria Novosti reported.

The accident highlights the plight of migrant workers in Russia. There are several thousands of foreign workers who are toiling in construction sector and in markets in inhuman conditions.

The incident came just hours after a blaze at a under construction skyscraper in Moscow, which would be the tallest building in Europe after its completion.