12 killed in Moscow market fire Another official said the workers probably left the space heater on all night to stay warm during the frigid Moscow spring. Overnight temperatures plunged below freezing and much of central Russia has been hit by snow. The fire could have started from the electric space heater. It was probable left on all night because the structure was turned into living quarters," an unnamed investigator told ITAR-TASS. Police said they have opened a criminal investigation but have not yet pressed any charges against the market owners. Russia's migration service estimates that there are 700,000 Tajiks living officially in the country - a tenth of their home country's population of just under seven million. Tajikistan was wrecked by a brutal civil war in the early 1990s and then experienced nearly two decades of ethnic tensions and endemic drugs trafficking that hampered sustainable growth. Its economy remains in tatters and some analysts estimate that up to half of Tajikistan's young male population is currently trying to make a living in Moscow and other major Russian cities. The predominant majority of the migrants who arrive in Moscow do so without acquiring the official city worker permits that the Russian capital has required since Soviet times. Their employment is therefore never officially reported to the authorities and many end up living in Moscow apartment block basements or makeshift residences. Seven migrants were killed in January 2009 when a fire swept through an underground Moscow garage they were building and had also used as a temporary living shelter. Another seven died in May 2011 when a fire engulfed an old abandoned building in central Moscow. The presence of Central Asian nationals and workers from the predominantly Muslim Caucasus region has also stirred racial tensions in the Russian capital and resulted in repeated deadly attacks. President-elect Vladimir Putin had vowed to reinforce migration controls while serving as prime minister for the past four years and won a strong following from Russian nationalists while heading the Kremlin in 2000-2008.