ROME –Italian elections that will determine Prime Minister Silvio Berlusconi’s political future and may have ramifications for his Mediaset TV empire were too close to call late Monday.

While exit polls initially put center-left incumbent Romano Prodi in the lead, estimates based on a partial vote count gave Berlusconi’s conservative bloc a narrow majority in the senate, with the two sides running neck-and-neck in the chamber of deputies.

A winner may not be announced until this morning and neither candidate made a public statement Monday night.

Voter turnout was an exceptionally high 84%, capping a contentious campaign during which Berlusconi’s use of television as a political tool became a dominant issue.

If the mogul-turned-politician loses, the center-left has vowed to pass a conflict-of-interest law that could force him to sell Mediaset or leave politics. Berlusconi has said his political career will not end regardless of the vote’s outcome.

One thing the election’s partial results make clear is that Berlusconi’s Forza Italia remains the country’s largest single political force, with more than 20% of early results going in Forza’s favor.

Berlusconi, who is running for his third stint as prime minister, has governed Italy for five years — the longest period in power since the end of WWII. During his reign, Mediaset’s profits have increased fourfold, with net profit rising almost 10% to $722 million in fiscal 2005, announced in March.

On Monday, Mediaset stock closed up 2% after dropping immediately after the initial exit polls.

If Prodi, an economics professor and former EU Commission chief, wins, he is expected to introduce more stringent limits on Mediaset’s advertising intake, among other measures intended to favor media pluralism.