Thousands of tons of oil are at risk of pouring into the sea off the coast of China after a tanker collided with a freighter.

An Iranian oil tanker carrying 150,000 tonnes of crude oil is spewing its cargo into the East China Sea.

It s after the Iranian vessel Sanchi struck Hong Kong-registered CF Crystal about 160 miles (257km) off the coast of Shanghai.

The tankers 32 crew members remain missing.

Environmental disaster

Chinese state media CCTV has shown pictures of the tanker ablaze amid billowing plumes of thick dark smoke.

Chinese authorities have said the tanker was carrying nearly 1 million barrels of condensate - an ultra light crude oil.

The tanker is now on fire and is spilling its cargo into the sea, authorities have said.

A Chinese vessel is dispatched to rescue crew members following the oil tanker collision, 08-01-2018. Image: Xinhua/Xinhua News Agency/PA Images

Missing crew

A spokesperson for China’s Ministry of Transportation confirmed the tanker’s 32 crew members remain missing.

He said rescue efforts were ongoing with four rescue ships and three cleaning boats sent to the site.

All 21 Chinese crew members of the Crystal, which was carrying grain from the US, have been rescued.

Bermuda Triangle

The collision is the latest of dozens of shipping accidents in a region that has recently been dubbed the new Bermuda Triangle, because of the number of ships that founder there.

30 Iranians and two Bangladeshis were on board the Sanchi when it was involved in the collision.

South Korea's coast guard has sent a ship and an airplane to assist the search effort.

The size of the oil slick spilling from the Sanchi is not currently known.

Asked about the 30 Iranians, an unnamed official in Iran's Oil Ministry told the AP: "We have no information on their fate. We cannot say all of them have died, because rescue teams are there and providing services."

The official said the tanker had been rented by a South Korean company and was on its way to South Korea.

Dangerous waters

Last year, German newspaper Die Welt carried out research which found the South and East China Seas and the seas around Indochina, Indonesia, the Malay Peninsula, the Korean Peninsula and Japan were the most dangerous in the world.

Total losses in 2016 according to the paper were 33 ships.

The risks presented by the region's seas led the paper to headline the article "The new Bermuda Triangle lies in front of China."

The Bermuda Triangle was a mythical area of the Atlantic Ocean between the Caribbean and Bermuda where dozens of ships and planes inexplicably sank or went missing in the 19th and 20th centuries.

Several US Navy ships have also ran into difficulty in the seas between Singapore and Japan, with the worst crash tearing a hole in the USS John S McCain and leaving 10 sailors missing.

Analysts say the region is so dangerous for ships because of the sheer amount of cargo being transported through its waters.

Reporting from IRN ...