BEIJING, China - Two bodies and the Black Box was recovered from the Panama-registered Sanchi oil tanker, that was carrying 136,000 tons or around 1 million barrels of oil from Iran to South Korea.

Earlier this week, the oil tanker that has been ablaze for days off the coast of Shanghai exploded in the East China Sea, forcing rescue boats searching for 31 missing sailors to retreat.

A week back, the oil tanker collided with the Hong Kong-registered CF Crystal freighter in the East China Sea and the tanker has been ablaze since then, drifting in the waters between Shanghai and southern Japan.

Officials said that 30 Iranian and two Bangladeshi sailors were onboard during the collision and on Saturday, bodies of only three of the 32 crewmen - 30 Iranians and two Bangladeshis - have so far been found.

Further, the four-member salvage team has also recovered the ship's "black box" recording unit.

On Saturday, the Chinese transport ministry said in a statement, "At 0837 (0037 GMT), four rescuers equipped with masks and bottles of oxygen were placed at the deck at the back of the Sanchi with the help of a crane. They discovered the bodies of two sailors in a lifeboat."

The ministry also released a video showing rescuers wearing white helmets and orange jumpsuits walking on the tanker, whose grey metallic structure appears to have been devastated by fire.

The ministry has stated, "After recovering the black box, the rescuers tried to reach the communal areas (....) But the temperature reached 89 degrees Celsius (192 degrees Fahrenheit) and they could not enter."

A team of Iranian commandos have now joined the operation.

A total of 15 vessels are taking part in the salvage operation, including ten Chinese, two Japanese and one South Korean vessel - all carrying out the rescue operation, oil recovery and firefighting.

According to China's Ministry of Transport, the CF-Crystal had been transporting food from the U.S. to the Chinese province of Guangdong, and had 21 crew members on board during the collision but all of them have been rescued.

According to the ministry, 14 vessels were engaged in the search for the missing sailors in the tanker's vicinity before the explosion.

Officials also added that the extent of the spill remains unclear, and cleanup boats are also on hand to deal with light crude spilled in the accident.

According to the ship-tracking site marinetraffic.com, the Sanchi is 900 feet long and displaces more than 85,000 tons.

It is almost as big as the U.S. Navy's Nimitz-class aircraft carriers.

Iran's Shana news agency said in a statement that the Sanchi's cargo was worth around $60 million and the oil it was carrying had been purchased by South Korean customers.