A fire that broke out among tents at a construction site in the Turkish city of Istanbul killed at least 11 workers late Sunday, media reported. \"Between 11 and 14 workers are believed to have died in the fire,\" local mayor Necmi Kadioglu told the state-run TRT television from the scene in the Esenyurt district of the city. \"This is the site of a shopping mall. It appears the fire has something to do with the heating problem as it is freezing here and right now it is minus one degree,\" he added. Firefighters put out the flames as ambulances attended the scene, the private NTV television reported. While the cause of the fire has not yet been established, media reports have suggested it may have been caused by a short circuit.