Voicing deep concern over murder of thinkers and recent incidents of hate in the country, he said the suppression of right of dissent cannot be allowed.
Singh described such incidents as a "blatant violation of right to freedom of thought, belief, speech and expression by some violent extremist groups".
"The assault or murder of thinkers are no more than disagreement with their views or because of the food they eat or their caste cannot be justified on any ground. Nor can be suppression of the right to dissent be allowed.
"All right thinking persons in our country have condemned such incidents in the strongest terms as an assault on our nationhood...Unity and respect for diversity, secularism and pluralism are vital for the survival of the republic," he said.
He was speaking after inaugurating the two-day national conference on the theme -- "No peace without freedom; No freedom without peace: Securing Nehru's legacy and India's future: Agenda for Action" organised by Rajiv Gandhi Institute of Contemporary Studies, New Delhi, ahead of the 125th birth anniversary of Jawaharlal Nehru.
The goal of the conference is to develop an agenda for action for securing and strengthening the cornerstone values of the Indian Republic as laid down by Nehru.