Protestors gathered outside the UN office with placards criticising the UN for failing to stop the massacre of tens of thousands of Tamils during the final stages of the armed conflict in 2009.
They also chanted slogans calling for an “independent international inquiry into genocide” and a referendum to establish an independent Tamil state in the North-East of the island.
Chennai police officers detained more than 50 activists from the Tamilar Vidiyal Katchi following the protest.