An Iranian oil tanker engulfed in flames has sunk eight days after a collision off the Chinese coast, state media said Sunday, with some 30 crewmen still missing. 

The tanker Sanchi, carrying 136,000 tonnes of light crude oil from Iran, has been ablaze since colliding with the CF Crystal, a Hong Kong-registered bulk freighter, on January 6.

"According to the latest news from the State Oceanic Administration, the 'Sanchi' has sunk in its entirety," the official Xinhua news agency said.