Rescue workers were searching the waters off the east coast of China in a desperate hunt for 32 missing sailors after an oil tanker collided with a cargo ship on Saturday.

The Iranian tanker, Sanchi, flying under a Panamanian flag, was a wall of flames and thick black smoke as rescuers hunted for survivors 160 miles off the coast. The tanker was carrying about a million barrels of natural gas condensate, or light oil, Bloomberg reported.

All of the missing 32 men ― 30 Iranians and two Bengalese ― were from the tanker, reported the China Global Television Network. All 21 Chinese aboard the Hong Kong cargo ship were rescued, said the TV network.

Search and rescue operation under way as 32 went missing after two vessels collided off the east coast of China; A Panama registered oil tanker is on fire pic.twitter.com/RslNE08cyd — CGTN (@CGTNOfficial) January 7, 2018

“Sanchi is floating and burning as of now,” said a statement from China’s Ministry of Transport, the BBC reported. “There is an oil slick and we are pushing forward with rescue efforts.”

Eight Chinese ships and a South Korean coast guard ship and helicopter were mobilized in the search for survivors.

The tanker had been sailing to Daesan, South Korea, from Kharg Island, Iran. It’s owned by the state-run National Iranian Tanker Co.

The cargo ship, the CF Crystal, was transporting grain from the U.S. to Guangdong province in southern China, the BBC reported.

It wasn’t clear what caused the accident.

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