Fire swept through a market warehouse in Moscow Tuesday killing at least 17 people, all thought to be migrant workers, Russia\'s Emergencies Ministry said. A Moscow migration services spokesman said officials were working to identify the victims, a difficult task because \"they are all badly burned,\" RIA Novosti reported. \"We believe they were migrant workers who lived at the market,\" an Emergencies Ministry spokesperson said. \"We are now trying to determine which republic they came from.\" Police said the fire may have been caused by a heater that hadn\'t been turned off. Overnight temperatures were around 32 degrees Fahrenheit. A representative for investigators told the Gazeta.ru online newspaper the death toll \"will certainly rise.\" One woman who was looking for friends told RIA Novosti she \"only saw burned bodies, hands and legs. It wasn\'t clear who was burned.\" She said the victims lived and worked at the market. Unconfirmed reports indicated the victims lived in cramped conditions at the warehouse and that and that there were no direct exits from their living quarters to the street. Police said they opened a criminal investigation, but have not yet brought charges against market owners.