Ships and aircraft from South Korea and the US are aiding in rescue efforts, which have been hampered by fierce fires and poisonous gases that have engulfed the tanker and surrounding waters.
All 32 crew from Sanchi - 30 Iranians and 2 Bangladeshis - remain missing, and the ministry said that the 21 Chinese crew from CF Crystal have all been rescued.
"Unfortunately, up to this moment, there is no news of the crew", he said. One body has been recovered, Iran's Ports and Maritime Organization said Monday.
By comparison, the Exxon Valdez was carrying 1.26 million barrels of crude oil when it spilled 260,000 barrels into Prince William Sound off Alaska in 1989. "There is an oil slick and we are pushing forward with rescue efforts".
An official in Iran's Oil Ministry, who spoke to The Associated Press on condition of anonymity as he was not authorized to speak to journalists, said that 30 of the 32 crew members on the ship were Iranians. The Foreign Ministry said in a separate statement that the cause of the incident was under investigation.
"Pollution caused by the leak is certain, but compared to the wide watershed of the Yangtze River estuary, the 136,000 tons of oil should not cause too serious a problem", Mu said.
That was nearly twice the size of the Exxon Valdez spill, which ravaged Alaska's coast in 1989.
Reuters ship tracking data shows Sanchi was built in 2008 and was managed by the NationalIranian Tanker Co (NITC).
The Sanchi, owned by National Iranian Tanker Co, was en route to South Korea when the collision happened. National Iranian Tanker describes itself as operating the largest tanker fleet in the Middle East.
China's English-language state broadcaster CGTN posted a video on Twitter Monday afternoon showing the fire from the oil tanker seemingly under control as a second vessel sprayed the tanker with water.
Hanwha Total was not immediately available for comment. In August 2016, an Iranian-owned tanker collided with a container ship in the Singapore Strait with no injuries or environmental contamination.
The vessel, registered in Hong Kong, was carrying 64,000 tonnes of grain from the United States to China's southern province of Guangdong, the government added. Norwegian ship insurer Skuld has confirmed it was the lead hull insurer for the tanker and the protection and indemnity (P&I) insurer for CF Crystal.
Bulk carrier suffered comparatively small damages, meaning that CF CRYSTAL, most probably, struck SANCHI.