This has increased concerns that the ship may break up and sink.
The Sanchi was carrying almost 1 million barrels of condensate, a type of gassy, ultra-light oil, when it collided Saturday evening with a freighter 257 kilometers (160 miles) off the Chinese coast and caught fire.
Bad weather is hampering efforts to contain a fire and oil spill off the coast of Shanghai three days after a collision between an Iranian-owned oil tanker and a Hong Kong-flagged bulk carrier in the East China Sea.
Search and firefighting efforts resumed Thursday after an onboard explosion rocked the tanker Wednesday.
The ship, which has been ablaze for nearly a week since it collided with another vessel on Saturday night in the East China Sea, was about 286 km (178 miles) northwest of Sokkozaki on the island of Amami Oshima as of 0700 GMT on Friday, the Japan Coast Guard said in a statement.More news: White House addresses President Trump's fiery "sh*thole" comments
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Sanchi was carrying nearly one million barrels of highly flammable crude oil to South Korea with 32 crew members on board - 30 Iranians and two Bangladeshis.
The 21 Chinese crew members on the CF Crystal, carrying grain from the U.S., were rescued.
The spokesman said that Chinese authorities turned down an offer from the Japanese Coast Guard to help, saying it would ask for help when needed. Aboard the oil tanker were a total of 32 people, 30 of them are Iranian citizens and two crew members from Bangladesh.
However, fears still remain that the oil tanker could explode at any moment due to the high volatility of the condensate oil, likely killing all the crew members on board.
One body has been found but 31 sailors - mainly Iranians - remain missing with officials in Iran hoping they have found sanctuary on an unaffected part of the vessel.