Italian political parties failed to reach a consensus on the candidate for the country's presidency, with two rounds of voting in the parliament remaining inconclusive Friday.
A crucial fourth round of voting was due to take place Saturday, Xinhua reported.
Over 500 blank ballots were cast in voting Friday, in a joint session of both houses of the Italian parliament and a similar result had come out of the first round held Thursday.
Constitutional court judge Sergio Mattarella was the sole candidate advanced by Prime Minister Matteo Renzi and his centre-left Democratic Party (PD), and he gained support from other minor leftist and centrist parties.
The candidacy of the 73-year-old judge, who entered politics as a Christian Democrat in the 1980s and served as a minister in several cabinets, was however, not accepted by former prime minister, Silvio Berlusconi, and his centre-right opposition Forza Italia (FI) party.
Mattarella also faced resistance from the smaller New Centre-Right (NCD) party of Interior Minister Angelino Alfano, which is part of the ruling coalition.
Both centre-right forces were angered by Renzi's decision to promote Mattarella as the sole candidate without consulting them.
A broad two-third majority was required to elect Italy' s president in the first three rounds of voting, which meant 673 votes out of an assembly of 1,009 lawmakers and regional representatives.
From the fourth round onwards, a simple majority of 505 votes will suffice.
Prime Minister Renzi's party along with minor centre-left allies, and possibly some lawmakers from the anti-establishment Five Star Movement (M5S), would have the "strength" required to secure the election of judge Mattarella without further support.
However, this solution would imply some risks.
A political pact on major reforms was, in fact, struck by Renzi and Berlusconi in early 2014.
A breach between the prime minister and the two main centre-right parties over the presidential election may threaten both the on-going reform process and the endurance of the coalition cabinet.
The process to elect the new Italian head of state began in the lower house Thursday, two weeks after the early resignation of the 89-year-old Giorgio Napolitano.
