New Delhi, Nov 27 (ANI): Former Prime Minister Manmohan Singh advised incumbent Prime Minister Narendra Modi to exercise "due restraint". "My advice to PM is that he should exercise due restraint becoming of the office of PM. When he goes to states which are ruled by parties other than his, I think, has an obligation not to use the type of language which has now become a common practice," said Manmohan Singh at a book launch event in New Delhi. Manmohan Singh added, "The prime minister of a country must set an example. He is the prime minister for all the citizens of our country and his conduct must be worthy and consistent with that obligation that he/she has as prime minister."