The Panama-registered tanker "Sanchi" was sailing from Iran to South Korea carrying 136,000 tonnes of crude oil when it collided with a Chinese freighter, Reuters reports. Its entire 32 person crew remained missing Sunday as the fire continued to blaze.
The AP reports that an official in Iran's Oil Ministry said 30 of the tanker's 32 crew members were Iranians.
"We have no information on their fate," he told the news agency. "We cannot say all of them have died, because rescue teams are there and providing services."
State media reports that China dispatched several vessels to search for and rescue crew members as the vessel burned. South Korea also sent a ship and helicopter to aid the rescue and clean up efforts.
The environmental impact was not immediately clear, and the Chinese government did not give details as to the size of the spill. The ship was carrying almost a million barrels of condensate, an ultra light crude oil.
The AP reports that this is the second collision for the National Iranian Tanker Company in less than two years. In 2016 one of its tankers collided with a Swiss container ship in the busy Singapore Strait, though that incident caused no injuries or oil spill.
All of the 21 Chinese crew members were rescued from the CF Crystal, which suffered only "non-critical" damage in the crash, according to Reuters.