The tanker, operated by National Iranian Tanker Co, was sailing from Iran to South Korea, carrying 136,000 tonnes of condensate, when it collided with the ‘CF Crystal’, about 160 nautical miles off the coast, near Shanghai and the mouth of the Yangtze River Delta, on Saturday evening. The vessel went ablaze and has been on fire since then.

The ‘Sanchi’ was carrying a total of 32 crew members, all of whom were reported missing, while one of them has been found so far.

China's Ministry of Foreign affairs said that 12 vessels were searching for the 31 missing crewmen in the tanker's vicinity before the explosion, while trying to clean up any spilled light crude. The rescue teams were forced to retreat following explosion.

According to South Korea’s Ministry of Oceans and Fisheries, the vessel could burn for two weeks up to one month, potentially expelling its bunker fuel, or the heavy fuel oil that powers a ship’s engines and contaminating the waters, Reuters reported.

The Chinese freighter involved in the collision, 'CF Crystal', has berthed in Zhoushan in order to be investigated.