Italy election: Results point to impasse
With most results in from Italy's election, the houses of parliament appear split between left and right, causing new anxiety in the eurozone.
Pier Luigi Bersani's centre-left bloc is set for a narrow win in the lower house but Silvio Berlusconi's centre-right may take control of the Senate.
A protest movement led by comedian Beppe Grillo surged into third place, attracting a quarter of the vote.
The election comes amid a deep recession and tough austerity measures.
The vote marks a return to full-blown democracy for Italians after the technocratic government of Mario Monti whose attempts to reduce spending caused widespread public resentment.
Control of both the lower and upper houses of parliament is needed in order to govern.
Milan's stock market soared nearly 4% when exit polls suggested a clear Bersani victory - but lost nearly all of its gains when projections began to show Mr Berlusconi winning a sizeable vote. Italy's 10-year borrowing cost fell but then rose again to close slightly higher at 4.49%.
"It is clear to everyone that a very delicate situation is emerging for the country," Mr Bersani said as the last of the votes were being counted.
It was market pressure, with a borrowing cost of well over 6%, that forced Mr Berlusconi to resign as prime minister in late 2011.
Correspondents say Italy's EU partners and the financial markets want to see a stable outcome to the election, with a commitment to reform and debt-reduction.
The BBC's Europe editor, Gavin Hewitt, says Brussels and Berlin would like to see Mr Bersani form a governing coalition with Mr Monti.
They fear that an uncertain outcome could lead to Greek-style paralysis in the eurozone's third largest economy, he says.
The deputy head of Mr Bersani's Democratic Party sought to downplay speculation about a repeat election after comments from another party official.
With returns from almost all districts processed, Mr Bersani's centre-left bloc had won 29.57% of the vote for the lower house (Chamber of Deputies) to 29.15% for Mr Berlusconi's bloc.
Mr Grillo's Five Star Movement had 25.54% and the centrist list led by Mario Monti 10.57%.
"We've started a war of generations," Mr Grillo said in an audio statement on his website which taunted the leaders of the mainstream parties.
"They are all losers, they've been there for 25 to 30 years and they've led this country to catastrophe."
Mr Bersani was projected initially to win a majority in the Senate, where seats are decided region by region. However, as the results came in, Mr Berlusconi's bloc moved ahead in three of the four key swing regions.
He was set to win in the northern region of Lombardy, as well as the central region of Campania and Sicily.
Mr Bersani has pledged to continue with Mr Monti's reforms but suggests current European policy needs to do more to promote growth and jobs.
The election was called two months ahead of schedule, after Mr Berlusconi's party withdrew its support for Mr Monti's government.
Enrico Letta, Mr Bersani's deputy, said the centre-left bloc should win the vote in the lower house and would have the responsibility for trying to form a new government.
Speaking after the party's economics spokesman, Stefano Fassina, publicly suggested a new election would have to be called in order to form a stable government, Mr Letta said: "Returning to the vote immediately does not seem today seem the best option to follow."
At party headquarters in Rome, one candidate, Alessandra Moretti, told AFP news agency the results gave "the impression of a country torn apart".
Accepting that Five Star had "succeeded where traditional politics has failed", she hinted at possible collaboration with Mr Grillo's party - "a relationship that could give us an agreement on concrete laws".
Mr Monti said in a message on Twitter he was "satisfied" with his bloc's showing. While the mood was sombre at campaign headquarters, one candidate, Mario Giro, suggested the former prime minister could yet play a central role.
"If the current results are confirmed, we'll have two big coalitions that will have to work together," he told AFP. "Monti would be a pivot between the two. He'll be central."
But Mr Grillo's camp played down the prospect of co-operation with Mr Berlusconi.
In his home city, there was shock and delight among Five Star candidates, who celebrated the party's huge success at a bar, AFP reports.
"This is a moment when you feel a bit weird because we are ordinary citizens, we don't have political experience," Cristina De Pietro said. "We have a lot to learn."