Addressing the 12th South Asia conference here, Singh said it is essential that terrorists and their ideological and financial networks are cut off and do not receive state support.
"India is engaged in conversations with its neighbours except one country in order to develop a joint approach for regional peace and security.
"True pathway to regional peace and security lies in understanding each other's sensitivities and following basic principles of non-interference in each other's internal affairs," he said.
Singh asserted the South Asia region must unite in their efforts to defeat terrorism. Mumbai, Pathankot, Uri, and Pulwama attacks are grim reminders of state-sponsored terrorism by a neighbouring country.
"Pakistan must take demonstrable steps against terror groups," he said.