Tamil Nadu Chief Minister J.Jayalalithaa has urged Prime Minister Narendra Modi to secure the release of Indian fishermen and their boats from Sri Lankan custody.In a letter to Modi, the text of which was released to media on Saturday, Jayalalithaa said seven Indian fishermen and their fishing boat were apprehended by Sri Lankan authorities on October 1."This latest belligerent act of the Sri Lankan Navy perpetrated on innocent and unarmed Indian fishermen adds to the immense frustration that has built up among the fishermen community of Tamil Nadu," she wrote.According to her, the repeated apprehensions of Indian fishermen by Sril Lanka is done to intimidate them and prevent them from fishing in their traditional fishing waters in the Palk Bay."I request you to take immediate action through diplomatic channels to secure the release of our 7 Indian fishermen and their fishing boat apprehended on October 1, 2015 as well as the release of the 28 fishermen and 31 fishing boats which are still in Sri Lankan custody and arrange for their immediate repatriation," she said.