Rome, April 23 - Pier Luigi Bersani, the outgoing leader of the Democratic Party (PD), on Tuesday said the party had been on the edge of a "very grave crisis" as repeated efforts to elect a PD-backed president to replace Giorgio Napolitano late last week faltered. Napolitano, 87, was eventually re-elected after five rounds of voting by Italy's parliament which saw splits emerge in the PD itself, leading to Bersani's resignation as party chief. "I announced my resignation after PD nominees (former Senate Speaker) Franco Marini and (former centre-left premier) Romano Prodi were rejected" by party rebels, Bersani said. Bersani also accused "many" of the party's electors who he said didn't keep their promises to participate in "formal and collective decisions in a crucial moment". "We were on the edge of an extremely grave crisis without precedent," the outgoing PD leader said. In an effort to dispel fears that the PD was rudderless, Bersani said: "the party is not in a state of abandon, the leadership is working, as are the parliamentary groups, the vice secretary and the treasurer - all in the fullness of their powers".