They also sought an international inquiry into the alleged human rights violations and a referendum on separate Eelam.
R. Prabhakaran, one of the students, said they wanted to erect a pandal but were forced to sit in the open as the police denied permission to their agitation citing the Lok Sabha election.
Senthil Kumar, a youth who claims to run a pro-Tamil organisation, Inmurai Tamil Kazhagam, has also joined the fast expressing support for the cause.
The students urged the Centre to honour the resolution adopted in the State Legislative Assembly on the Sri Lankan Tamils issue and called for steps to stop attacks on Tamil Nadu fishermen by Sri Lankan Navy and retrieval of Katchatheevu.