Police have strengthened security at the Pooluvapatti Sri Lankan refugee camp in Coimbatore, India following a clash between members of the camp and a Hindu outfit on Saturday, The Hindu newspaper reported.Coimbatore District (Rural) police have arrested four persons in connection with the incident. One Siva, 52, intervened in the dispute between Vijay and Antony. “A few persons from the camp allegedly pushed Siva. Siva informed his son Susheendran of the incident. He took up the matter with the Hindu Munnani men. A group of over 100 men entered the camp at 11.30 p.m. leading to a clash,” the police said. According to the police, a volleyball match held at the camp led to the fight between Hindu Munnani functionaries and camp inmates.