New Delhi: Poll strategist and Janata Dal (United) Vice-President Prashant Kishor has come out hard against jailed Rashtriya Janata Dal (RJD) chief Lalu Prasad and challenged him for an open debate over his alleged claims on RJD-JD(U) merger.

Taking to Twitter, Kishor wrote, 'Those convicted or facing charges of abuse of public office and misappropriation of funds are claiming to be the custodians of truth.” He then challenged Lalu for an open debate in front of media to expose the truth.

Kishor's comment comes a day after Lalu Yadav's wife Rabri Devi Friday claimed that the poll strategist had met her husband Lalu Prasad with the proposal that the RJD and Nitish Kumar's JD(U) merge together and the new entity thus formed declare its "prime ministerial candidate" ahead of the Lok Sabha polls 2019.

Lalu, in his recently published memoir "Gopalganj to Raisina", alleged that JD(U) chief Nitish Kumar had tried to realign with Bihar's mahagathbandhan (Grand Alliance) after joining the National Democratic Alliance and sent his emissary Kishor to him on five occasions.

Kishor has repeatedly denied meeting Lalu with such a proposal.

Terming Kishor's statement a "blatant lie", Rabri Devi said, "I got infuriated and asked him to go away as I had no trust left in Bihar chief minister Nitish Kumar following his betrayal," the RJD national vice-president, who is also the leader of the opposition in the legislative council, told a regional news channel here, reported news agency PTI.