PLEASE NOTE: EDIT CONTAINS CONVERTED 4:3 MATERIAL

The fire at this fuel storage plant in western India broke out on Saturday and is threatening to spread.

Fire-fighters have been battling through the night to bring it under control.

At least four workers at the plant are unaccounted for. A relative fears the worst.

SOUNDBITE: HARSH NARAYAN, RELATIVE, SAYING (Hindi):

"They were doing some railing work over the tank. At that moment the blast happened so I guess they might have died there on the spot. Among them are my cousins Jalandhar Chaudhary, Ravi Swain and Raut Kar, and one more whose name I don't know."

The blaze, near Surat city, broke out in a tank containing thousands of litres of petrol.

Fire crews from neighbouring cities have been drafted in to help combat the flames.

The storage terminal is operated by the state-run Indian Oil Corporation.