HAIKOU, Oct. 20 (Xinhua) -- An oil tanker carrying 3,400 tonnes of naphtha exploded at a port in south China's island province of Hainan Thursday afternoon and one person remains missing, local authorities said.

According to the provincial fire brigade, the explosion occurred during an unloading operation in a port in Dongfang City at about 1 p.m. Eleven people onboard escaped but a further six were trapped.

Nine vehicles and 50 rescue workers rushed to the scene and have so far rescued five people. One person remains missing.

Rescue workers said there have been three explosions in the engine compartment, and they are trying to dilute the oil present and cool the ship.