Reuters is reporting that the political gridlock that is preventing the formation of a government following the elections a week ago, could lead to a new vote as soon as June.

Former comic Beppe Grillo, head of the Five Star Movement that received 25% of the vote, has refused to ally himself with any "establishment" party. His refusal makes it near impossible for the formation of a stable government.

n an interview on RAI state television late on Sunday, Bersani underlined his opposition to two of the options currently being floated - another technocrat government like the outgoing one led by Mario Monti or a grand coalition with Silvio Berlusconi's center-right.

That would leave only one possibility to avoid elections - Grillo's backing for the center-left, which won the lower house in the election but does not have enough support to rule in the Senate.

"Now (Grillo) must say what he wants, otherwise we all go home, including him," Bersani said.

Grillo has repeatedly said his populist movement would not give a vote of confidence to any government of established parties, although it could support individual laws.

The uncertainty in Italy, during a long limbo before talks to form a government begin after March 15, has unsettled international markets.

The spread between Italian 10-year benchmark bonds and German bunds - a measure of investor confidence - widened on Monday to an almost three-month high as the country entered its second week of gridlock.

Grillo last week called Bersani a "dead man talking" when he first made overtures to the 5-Star Movement, which became Italy's single biggest party in its first national test, taking a quarter of the vote.

Bersani's ultimatum may not work against Grillo and his tactics are apparently opposed by some of the leadership of his Democratic Party (PD).

The Genoese comic is widely believed to want to get back to the polls to wipe out the old order and boost his vote. He is also believed to fear his novice lawmakers could be suborned by cynical traditional politicians once they get into parliament.

"It's in his interest to go back to the ballot box as soon as possible," said Maurizio Pessato, vice chairman of polling institute SWG.

"Grillo can't win more than 8 million votes promising to get rid of the establishment and then immediately ally himself with the old guard," he added.

Grillo is taking a chance by refusing to join one side or the other. A significant faction in his party wants to join Bersani's leftist coaliton. 150,000 of them signed a petition on a Facebook page asking Grillo to change his mind.

But Grillo is playing his own game -- nothing less than to become prime minister while heading up the largest party in Italy.

What he does after that worries many both in Ialy and in Europe.