Beijing (CNN) An oil tanker that collided with a freight ship off the east coast of China was still on fire Monday and at risk of exploding, Chinese authorities said.

The Shanghai Maritime Bureau said Monday morning the vessel and leaked cargo were burning furiously and that fumes were hampering rescue efforts. It said that experts believed there was a risk the vessel could explode and sink.

"The poisonous gas ... is very harmful to rescue workers in the field."

Thirty Iranians and two Bangladeshi citizens went missing from the Panama-registered tanker SANCHI after the collision Saturday. Lu Kang, a spokesman for China's Ministry of Foreign Affairs, said Monday that one body had been found by search-and-rescue teams but the person's identity hadn't been confirmed.

"The environment and the conditions on the ground are not very favorable for search-and-rescue work and some crew members are still missing, Lu said.

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