QHA - At least 18 sailors are feared to be trapped on board an Indian submarine that caught fire after an explosion in a Mumbai dockyard, BBC reports. The blast occurred shortly after midnight and it took fire-fighters several hours to douse the blaze. Officials say the diesel-powered vessel was badly damaged and remains partly submerged at its berth. Many sailors managed to jump to safety. Rescue teams are on scene and some of the injured were taken to hospital. It is unclear exactly what caused the explosion on the INS Sindhurakshak, a naval inquiry has been set up to look into the causes of the incident. As reported this case is not the first accident happened at the submarine. The submarine is of Russian produce. India and Russia are long-time allies and Russia supplies about 70% of India's military hardware.