A fire onboard Bulgaria's Khan Asparukh tanker, caused by an explosion shortly after the tanker left Russia's port of Novorossiisk, has been localised. Four injured crew members have been taken to Novorossiisk in a pilot boat. A spokesman for the North Caucausian Frontier Guard Service has told RIA Novosti that, according to preliminary information, the immediate cause of the fire was the ignition of a cable. A coast guard boat, which is patrolling the area, has reported no traces of oil on the sea surface. The Khan Asparukh, which has a displacement of 7,000 to 8,000 tons, left Novorossiisk, loaded with crude oil. It was heading for the open sea, bound for a Greek port. At 5:55, there was an explosion onboard the tanker, which was followed by a fire, later localised. Currently, there are two Russian fire-fighting and rescue vessels near the tanker, Mars and Tuman, both from the port of Novorossiisk. According to the Frontier Guard Service's spokesman, the tanker will, most likely, return to Novorossiisk, but the final decision will be made after a conclusion is drawn on the tanker's state.