Sri Lankan Navy personnel on Sunday allegedly assaulted four Indian fishermen for not helping one of their colleagues, who fell in their boat while trying to jump in the vessel and suffered a fracture. The naval men also severed the anchor of the boat and destroyed fishing nets besides pelting stones at the fishermen, official sources said. Twenty fishermen were hurt in the incident and were admitted to hospital. Meanwhile, hundreds of fisherfolk from 54 hamlets in Puduottai and Karaikal observed fast at Nagapattinam for release of 210 fishermen.