Reports from Italy say centre-left leader Pier Luigi Bersani is to step down following politicians’ failure to elect a new president at the fourth attempt.
He told deputies from his Democratic Party (PD) that he would resign as soon as a president was chosen.
The centre-left’s preferred choice, the former EU Commission President and ex-Italian Prime Minister Romano Prodi, came top but was more than 100 votes short of the winning target. He later withdrew his candidacy.
The head of state’s election is seen as a vital step towards breaking the stalemate after February’s general election.
Bersani’s attempts to form a coalition failed and his inability to get a president elected show the extent of divisions even on his own side.
On the right, Prodi’s nomination was bitterly opposed by Silvio Berlusconi and Alessandra Mussolini’s far-right group.
There will be another attempt to choose a new president on Saturday.