In a scathing attack on Prime Minister Narendra Modi, former prime minister Manmohan Singh on Thursday accused him of lowering the dignity of public discourse and the gravity of the office of the PM by giving "hateful speeches" during the poll campaign.

In an appeal to voters of Punjab ahead of the seventh-phase of Lok Sabha polls on June 1, Singh asserted that only the Congress can ensure growth-oriented progressive future where democracy and Constitution will be safeguarded.

"The BJP thinks that the value of patriotism, bravery and service is only four years. This shows their fake nationalism," he said in a letter to voters of Punjab.

Mounting an attack on Modi, Singh said, "I have been keenly following the political discourse during this election campaign. Modi ji has indulged in the most vicious form of hate speeches, which are purely divisive in nature. Modi ji is the first prime minister to lower the dignity of public discourse, and thereby the gravity of the office of the prime minister.

"No prime minister in the past has uttered such hateful, unparliamentary and coarse terms, meant to target either a specific section of the society or the opposition. He has also attributed some false statements to me. I have never in my life singled out one community from the other. That is the sole copyright of the BJP," the former prime minister said.