Speaking to reporters here, Singh said Pawar is a widely accepted leader in the country.
"During his birthday event in New Delhi, all the political leaders irrespective of parties and ideologies attended the function, which shows how acceptable and a tall leader he is," Singh said.
Pawar should "take a lead to unite all the secular parties" to fight against BJP which indulges in "politics of polarisation", the senior Congress leader said.
BJP and other right-wing organisations eulogised Nathuram Godse, Mahatma Gandhi's assassin, and books and plays were being written to turn him into a hero, Singh said.