Italian comedian-turned-politician
Beppe Grillo, whose Five-Star Movement (M5S) defied expectations to come third in last weekend's elections, has ruled out a coalition with the centre-left.
Pier Luigi Bersani's Democratic Party (PD) won a majority in the Chamber of Deputies but fell short in the Senate.
Mr Grillo told the BBC that he expected Mr Bersani to agree a deal with Silvio Berlusconi's People of Freedom (PdL).
Our media calls Beppe Grillo a clown or a maniac. This view is very prejudiced. Grillo gives the Italians hope. He is supported by nobel price winners and professors. Grillo wants a better democracy. With more participation. Not less. Far away of the fossiled structures that are ruling today. In times of nationwide poverty, the forced "socialisation of financial losses" and the manipulation of their media through big corporations, the Italian people do not want to pay for the investment mistakes of a couple of rich investors.
Our nations are being extracted of their finances. Through gambling, debt and taxes. Where does this money go? What are the real reasons for our current crisis? Do we own our money? It is time to ask questions and understand what drives the engines of our western world. In the end, this is something that we should already have learned as school kids.
Mr Grillo told the BBC he would not support any new government
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Italian comedian-turned-politician Beppe Grillo, whose Five-Star Movement (M5S) defied expectations to come third in last weekend's elections, has ruled out a coalition with the centre-left.
Pier Luigi Bersani's Democratic Party (PD) won a majority in the Chamber of Deputies but fell short in the Senate.
Mr Grillo told the BBC he expected Mr Bersani to agree a deal with Silvio Berlusconi's People of Freedom (PdL).
The inconclusive polls have pushed up borrowing costs for the government.
On Wednesday, the Italian treasury sold 4bn euros (£3.45bn) of new 10-year government bonds on the financial markets at a yield of 4.83%, up from 4.17% at its last sale in January, and 2.5bn euros of new five-year bonds at a yield of 3.59%, up from 2.94%.
BBC economics correspondent Andrew Walker says the latest rates are seen as bearable, but that the rises signal that investors want to see a strong Italian government, committed to economic reforms.
It is certainly possible that borrowing costs will rise further if the political uncertainty drags on for a long period, he adds.
'Dead Man Talking'
In an interview with the BBC, Mr Grillo said he would not support any new government and he expected fresh elections to be held within a year.
It's been days that [Pier Luigi Bersani] has been bothering the M5S with indecent proposals rather than resigning, as anyone else would have done in his place"
Beppe Grillo
Leader, Five-Star Movement (M5S)
"Today in Italy, what will happen is what happened before. The right and the left will get together and will govern a country of rubble that they are responsible for," he said.
"It will last a year. One. Maximum. Then there will be elections again. And once again, in the elections, the Five-Star movement will change the world," he added.
Mr Grillo said the M5S would decide whether to support specific legislation on a case-by-case basis.
Any attempts to persuade the movement to take part in a government were fake, he asserted.
The 64 year old also rejected the suggestion that he was inciting popular anger, saying he should be thanked for giving angry people hope.
"There was no hope. It was an anger without hope. It is anger without hope that creates violence," he explained.
"But anger with hope is a different kind of anger, an optimistic anger, it is not negative. We are containing this rage, so they should thank me. It is a democratic rage that is needed to go forward."
On his blog, Mr Grillo also published a mocked-up film poster depicting Mr Bersani as a "Dead Man Talking", based on the 1950 Italian comedy, 47 Morto Che Parla.
"Bersani is a political stalker," Mr Grillo wrote. "It's been days that he has been bothering the M5S with indecent proposals rather than resigning [the leadership of the PD], as anyone else would have done in his place."
The Democratic Party and its centre-left allies won a narrow victory in the Chamber of Deputies, but the Senate appears split with no party in control. Mr Berlusconi's centre-right coalition is the second biggest bloc in the upper house. The seats under Mr Grillo's control in both houses could therefore prove crucial in making any coalition government viable.
On Tuesday, Mr Bersani outlined a series of policies for a PD-led government which appeared to mostly be in line with M5S's manifesto.
Pier Luigi Bersani suggested there could be agreement with Mr Grillo on a list of measures
He said any groups backing the government would have to vote for it in the confidence motion required when a new administration takes office, and urged Mr Grillo to "assume his responsibilities".
Meanwhile, a German opposition leader has made waves by describing Mr Grillo and Mr Berlusconi as "clowns".
The Social Democratic Party's candidate for chancellor, Peer Steinbrueck, told a rally in Potsdam that he was "shocked to a certain degree that two clowns have won" the Italian elections and made it clear he was referring to the two party leaders, calling the former prime minister "definitely a clown with a special testosterone boost". Mr Berlusconi has been embroiled in a series of sex scandals.
Italian President Giorgio Napolitano cancelled a dinner with Mr Steinbrueck after learning of his remarks, a spokesman for the SPD candidate said. Mr Napolitano is still due to meet Chancellor Angela Merkel in Berlin on Thursday.
Both Mr Grillo and Mr Berlusconi campaigned against the austerity measures imposed by Italy's technocratic Prime Minister, Mario Monti, which were supported by Mrs Merkel