A fire broke out in the Amurbunia area at Chandpai range of the Sundarbans East Zone on Saturday.
The fire originated this afternoon, said Kazi Muhammad Nurul Karim, divisional forest officer (DFO) of Sundarbans East Zone.
On information, the staff of the forest department, Community Patrol Groups, Morelganj fire brigade and local villagers are trying to douse the fire.
Fire is being extinguished by bringing water from Bhola River about two kilometres away.
Fire lanes have been cut to prevent the fire from spreading into the forest, said the officer.
DFO Nurul Karim also said that the fire might have originated from a cigarette. An investigation committee will be formed to find out the exact cause of the fire.
The forest officer could not confirm the overall damage of forest plants in the area where the fire originated.