The Sanchi tanker, heading to South Korea and registered in Panama, collided with the CF Crystal some 160 nautical miles off the coast near Shanghai.

The Iranian tanker was carrying 136,000 tonnes of condensate, an ultra light crude, an equivalent of under a million barrels worth around $60 million based on current crude oil prices.

South Korean customers had purchased the cargo on a Persian Gulf FOB basis.

The tanker, managed by the National Iranian Tanker Company, was insured by internationally credited insurers.

It was due to arrive at Daesan in South Korea from Kharg Island in Iran on Sunday, according to Reuters ship tracking.

The tanker’s 32 crew members were missing on Sunday.

South Korea has also sent a ship and helicopter to help, Reuters reported.

NITC has mounted an investigation to find the reason behind the incident, the company's managing director Sirous Kinaersi said.

Search for the missing crew of the tanker including 30 Iranians and two Bangladeshis continues.

Kianersi said NITC formed an emergency committee with senior company officials immediately after the news of the collision was transmitted to Tehran.

He also said that NITC has dispatched two vessels sailing in the region to the spot of the explosion to offer help to rescue operations.