Kolkata: Five fishermen had gone missing after a fishing trawler carrying a total of 16 fishermen capsized at the Bay of Bengal Coast after reportedly colliding with a Bangladesh Navy ship within the Indian waters, authorities said on Monday.

However, the Indian Coast Guard, whose patrolling team is trying to track the five missing fishermen, has yet to confirm whether the collision took place within Indian waters, which means that the Bangladesh Navy ship entered the Indian waters in an unauthorised manner.

It is learnt that the fishing trawler christened FB-Paramita-11 went deep-sea fishing on Sunday.

On early Monday morning, it reportedly collided with the Bangladesh Navy ship.

The fishermen on another fishing trawler, which was near FB-Paramita at the time of the collision, claimed that when the collision took place, the visibility in the area was too low because of dense fog.

Following prompt action by the other fishing trawler, 11 of the 16 fishermen travelling by FB-Paramita-11 were somehow rescued.

However, the other five fishermen travelling on the capsized fishing trawler went missing.

The information on this count surfaced after the second trawler came back to the shore and reported the matter to the state administration.

The Indian Coast Guard authorities were contacted, and a search operation started at the Bay of Bengal Coast to track the five missing fishermen.

At the time the report was filed, the five fishermen were untraceable.

Although no statement in the matter has been issued by the Indian Coast Guard authorities as yet, the Assistant Secretary of the West Bengal Fishermen Welfare Association, Bijan Maiti, told media persons that there is no confirmation either on whether the fishing trawler crossed the international marine border with Bangladesh or whether the Bangladesh Navy ship entered the Indian waters.

"In case of the second possibility, the issue becomes a serious matter. We have demanded a thorough investigation into the matter," Maiti said.