Forecasts for the Italian elections have left it too close to call, and hint at political gridlock.
It's looking increasingly unlikely that any party will win enough votes to form a government with a solid parliamentary majority.
That holds out the risk of months of uncertainty that could reignite the euro zone crisis.
Officials from both the center and left said a hung parliament could make the country ungovernable.
The center-left is holding onto a slim majority in the both houses of the legislature, according to latest projections. But the right — led by former Prime Minister Silvio Berlusconi — is closing in.
It appears neither side will be able to muster a majority in the Senate thanks to the success of maverick comedian Beppe Grillo. He looks set to capture a quarter of the vote with a program that includes holding a referendum on pulling out of the European Union and having the state pay a guaranteed salary to all citizens.
The latest projections, four hours after polls closed on Monday, show the center left with 29.2 percent in the lower house, Berlusconi with 28.6 percent and Grillo with 26.3 percent.
In the Senate, projections show the center left with 31.1, Berlusconi 30.5 and Grillo 24.9.
The final result could depend on the key region of Lombardy, where polls were showing a near neck-and-neck race.
The two-day vote, which began on Sunday, will decide who succeeds the government led by Prime Minister Mario Monti.
Monti was appointed to replace Berlusconi, who resigned.
Monti's party looked to be taking a battering from voters, garnering about 10 percent of the vote. But his centrists could still play a key role if they are able to forge a coalition with Bersani's Democratic Party in the Senate.
The anti-establishment comedian, Grillo, leading the Five Star Movement, seems to have benefited from a huge protest vote, picking up over 20 percent of the vote to come in as the second party.
Grillo's criminal record will prevent him from taking a seat in the parliament himself. He was convicted of manslaughter after an auto accident in 1980 in which three people were killed.
With election-day exit polls being notoriously unreliable, confusion and tension looks set to continue for hours ahead until official results come through.
The elections come during a deep recession and austerity measures imposed by Monti's government. The outcome will also likely affect the Italian government's commitment to austerity measures in the euro zone.
Watch GlobalPost's Raw Feed: Divided and disillusioned, Italians head to the polls (video)
Paul Ames reported from Brussels. Follow him on Twitter @p1ames.