NEW DELHI: BJP on Saturday stepped up pressure on Rahul Gandhi to back up his claim of vote fraud by emphasising that the Congress MP had not taken up EC’s challenge to swear by his charges on an affidavit, and that he quit Lok Sabha on “moral grounds” if he does not have faith in the poll body.A day after Rahul skipped meeting Karnataka CEO and rejected the suggestion that he back up his allegation by submitting them in the required format, BJP’s Gaurav Bhatia also sought resignations of MPs Sonia Gandhi and Priyanka Gandhi, besides CMs of Congress-governed states, if they did not have faith in polls.