According to officials, the fishing nets of 10 boats were snapped and 20 fishermen on board five boats attacked with plastic tubes around midnight yesterday.
The fishermen said when they were fishing in the mid-sea unaware of the International Maritime Boundary Line, the Lankan naval men came in five fishing boats and warned them against fishing in the area.
President of local fishermen's association B Sesuraja said most of the fishermen had to return empty handed due to the threat posed by the Sri Lankan naval men.
Out of the 523 boats for which fishing tokens were issued by the fisheries department, only 200 had put out to sea and the owners of the rest did not show interest, they said.