Although the full damage of the explosion remains unclear, the incident is just the latest setback for the multi-national rescue operation involving Chinese, South Korean, and American authorities working to locate the 31 missing crew members.
The Sanchi was carrying almost 1 million barrels of condensate, a type of gassy, ultra-light oil, when it collided Saturday evening with a freighter 257 kilometers (160 miles) off the Chinese coast and caught fire.
Iranian oil tanker "Sanchi" which collided with a Chinese freight ship in the East China Sea on Saturday is still on fire after several days.
An NITC spokesperson had previously suggested China might be more concerned with stopping a major oil leak in waters important to their fishing industry than rushing to save crew members.
Photos on the Ministry of Transportation's microblog showed thick black smoke pouring out of the ship on Thursday morning.
Bad weather at the sea has made the rescue and cleanup efforts hard.
"Since the vessel's engine room is not directly affected by the fire and is about [46 feet] underwater, there is still hope", spokesman Mohsen Bahrami told the Associated Press (AP).
Even after parts of it exploded, and while it's still on fire, an Iranian diplomat said Thursday the crew on the oil tanker Sanchi may yet be alive.
The tanker, run by Iran's top oil shipping operator National Iranian Tanker, hit the CF Crystal vessel that was carrying grain from the United States last Saturday.
The tanker was carrying 136,000 tonnes of condensate, a highly flammable ultra-light crude, to South Korea, but it's unlikely the spill will reach the country's shores.
Officials have not yet established the cause of the collision, which happened off the coast of China, near Shanghai.
Park said it's unlikely the oil will spread to South Korea at the moment because the tanker has moved 100 kilometers (62 miles) to the southeast.