Colombo, Jan 19 (PTI) An Indian fishing boat allegedly trespassing the International Maritime Boundary Line sank in Sri Lankan waters after colliding with a Navy vessel of the island nation and a search and rescue operation was underway for the missing fishermen, the Navy said here on Tuesday

The Indian boat sank in Sri Lankan waters about 8 nautical miles within the International Maritime Boundary Line (IMBL) northwest of Delft Island on Monday

Sri Lanka Navy said it had launched a search and rescue operation for the sunken Indian fishing boat and its fishermen

It said the ?Navy units on patrol carried out an operation to seize Indian fishing trawlers poaching in Sri Lankan waters trespassing the International Maritime Boundary Line (IMBL)," after observing more than 50 trawlers

As the operation was going on, one of the Indian fishing trawlers tried to evade the scene, making it collide with a Sri Lankan Navy vessel

"The collision also caused damages to the SLN Fast Attack Craft which was subsequently brought to Kankesanthurai harbour safely for repair work," the statement said

The Navy then commenced a search and rescue operation for the fishermen on the sunken trawler. An unknown number of fishermen were missing

The Navy said that it is quite evident that Indian fishing trawlers poaching in Sri Lankan waters were resisting their arrests

Relevant Indian authorities have also been informed about the development and an investigation into the incident is currently underway.

Fishermen from both countries are arrested frequently for inadvertently trespassing into each other's waters

During his five-day visit to India in February last year, Sri Lankan Prime Minister Mahinda Rajapaksa and his Indian counterpart Narendra Modi agreed to resolve the long-festering fishermen issue with a "humane approach".