Former Prime Minister Manmohan Singh has written a letter to President Ram Nath Kovind urging him to caution PM Narendra Modi against using unwarranted, threatening and intimidating language against Congress or leaders from any other party as it does not behove his position. The letter has also been signed by Congress leader Mallikarjun Kharge and Leader of Opposition in Rajya Sabha Ghulam Nabi Azad among others. "In the past, all prime ministers of India have maintained immense dignity and decorum in the discharge of the public or private functions It is unthinkable that in our democratic polity, the prime minister as Head of the Government would utter words which are threatening, intimidating in content and public warning to the leaders and members of the main opposition Party i.e. Indian National Congress," Manmohan Singh's letter to President Kovind read. The letter was sent in the context of a May 6 rally in Karnataka's Hubli that the prime minister attended. In its letter, the party has complained against the language used by the prime minister at the rally. "The threat held out by the prime minister to the INC's leadership deserves to be condemned. This cannot be the language of the Prime Minister of a constitutionally governed democratic country of 1.3 billion people. Such discourse whether in public is unacceptable conduct. The words used are intimidating with intent to insult and provoke breach of peace," the letter said further. INC COMMUNIQUE Letter to the President of India by Former Prime Minister, Dr Manmohan Singh; LoP Rajya Sabha, Leader of CPP in LS & other senior leaders pointing out the negation of Constitutional oath by PM @narendramodi, and his unacceptable conduct. pic.twitter.com\/WXAhFKgupQ \u2014 INC Sandesh (@INCSandesh) May 14, 2018 The letter went on to add that the Congress party is the oldest in India and has faced many challenges and threats. "The Congress leadership has always exhibited courage and fearlessness in facing threat and challenges. We would like to state that neither the party nor our leaders will be cowed down by such threats."