Singh admitted that Congress is not being able to counter BJP of social media.
"I have not seen a person, who is more coward and a bigger liar than Modi. If you fear countering this liar, you should go and sit at home.... If anybody from the BJP opposes us, he should be replied with in the same language that they use against us.
"Be fearless and write whatever you want against Modi. He, who fears does not live. They have a paid team of professionals and we are volunteers. Counter their propaganda everywhere you can," Singh said addressing a national convention of NSUI here.
Taking a jibe at Modi's recent 'chai pe charcha' campaign, the Congress leader directed NSUI workers to fight the BJP's prime ministerial candidate every where including at teashops.
"You have to counter his propaganda even at tea stalls. Do all the tea stalls belong to him. You go there. Fight him there and tell people how much untruth he speaks. Do not be scared in countering a liar like Modi."
Singh also admitted that Congress is not being able to counter BJP of social media.
"This is the age of social media. BJP and Sangh still dominate the social media space. We are not being able to counter them. We should be doing it," he said urging NSUI leaders to help increase party's reach on the new medium of communication like Twitter and Facebook.
Singh's pitch for calling a spade a spade and using the language used by RSS and BJP came even as party vice president Rahul Gandhi had for some time been advocating that Congress leaders should avoid indecent language and personal attack when criticising their opponents.
Even at the NSUI's convention today, Gandhi said, "Our focus is never on anger but love and brotherhood. We are a party of Mahatma Gandhi. Our focus is more on work and so is yours. This is our DNA. You should not leave it. How much the Opposition provokes you, I urge you not to fall in the trap. You work with love."
Singh, who has been a trenchant critic of Modi on social media and in public discourses, has been advocating for long that Congress should be unsparing in attacking Modi.
He did not hide his displeasure over lack of initiative in the party in attacking the Opposition.
"I have seen that if somebody opposes, then people nod their head," he said advocating an aggressive campaign against Modi and BJP.
"They (BJP) are trained in spreading lies and mischief. They are masters at distorting everything," he said drawing parallels of BJP and RSS with Joseph Goebbles, the Propaganda Minister of the Nazi government of Hitler.
Talking about the political challenges ahead of Congress, Singh said that there is a need to make the party cadre based, as both Left and BJP have the support of cadres.
"BJP without RSS is zero. RSS is cadre based. Our challenge is with the RSS. Congress party will have to become a cadre based party. This is the army of cadres," he said to the NSUI cadres as he lauded Rahul Gandhi's initiative to introduce elections in NSUI and Youth Congress.
He at the same time underlined the need to enlarge the role of these elected bodies and ensure that more people connected with Youth Congress come into the parent party.
Singh also took a dig at the trend of some party leaders joining other parties saying Congress needs durable assets (tikau maal) and not saleable assets (bikau maal).
He said that those joining politics should first be clear what ideology they want to follow and once they join the party on its basis, they should not be changing loyalties.
His comments came a day when a senior leader from Congress in Uttar Pradesh Jagdambika Pal quit Congress fuelling speculation of his joining the BJP. There are some similar desertions from Congress in other states. Singh also dismissed the predictions of opinions polls. Attacking Modi for his "lack of knowledge" of history and geography of India as well as of his own party BJP, Singh said, "Modi does not know India and he does not know his own party."
Singh asked excited NSUI workers from states not to clap and do sloganshouting only, when a group of young leaders cheered former Rajasthan Chief Minister Ashok Gehlot, who had NSUI roots.
Singh reminded them that the party had lost badly in Rajasthan in recent assembly elections.
"I want to tell the Rajasthan NSUI president that the biggest challenge lies in Rajasthan. Results of the state (assembly elections) are there to see. Gehlot worked so well. Yet we lost there. The battle ahead cannot be fought only through Zindabad slogans."
Gehlot termed Modi as an "anarchic leader" and attributed Congress defeat in Rajasthan due to a certain atmosphere created by the Opposition.
Assam Chief Minister Tarun Gogoi said that he worked in the state better than Modi as Gujarat was already a developed state.
"Modi follows the ideology of Hitler. He wants to concentrate power in his hands alone. He believes in dictatorship. We follow Mahatma Gandhi. Rahul Gandhi wants to give powers to every hand."