Prime Minister Benjamin Netanyahu and his Likud party declared victory in the election for the 20th Knesset following exit polls released Tuesday night, but the Zionist Union said the prime minister's celebrations were premature.
The turnout was 71.8 percent, the highest since 1999 and 4.1% higher than the 67.8% of the last Knesset race in 2013.
"Against all odds, a great victory for the Likud," Netanyahu wrote on Twitter. "A major victory for the people of Israel!"
The Likud won 28 seats according to an exit poll on Channel 2 and 27 according to exit polls on Channels 1 and 10. The Zionist Union won 27 seats in all three exit polls.
Netanyahu immediately called the leaders of right-wing and haredi (ultra-Orthodox) parties in an effort to begin the process of forming a government.
Zionist Union leader Isaac Herzog also began efforts to form a government, calling heads of parties that he believes could join a coalition led by him that would not include Likud and Bayit Yehudi. He formed a coalition negotiating team that has already started working.
"The Likud continues misleading," the Zionist Union said in a statement. "The right-wing bloc has shrunk. Everything is open until the final results are in when we will know which parties crossed the electoral threshold. All the spin is premature."
Zionist Union strategist Reuven Adler told Channel 2 he was surprised that Netanyahu had apparently succeeded in winning 28 seats. He lamented that Netanyahu's "panicking" strategy had worked.
The two main possible coalitions are a national unity government of 77 or 78 seats or a right-wing government with 63-66.
President Reuven Rivlin will summon party leaders to begin the process of selecting a candidate to form a government next week. Official results will only be available on March 25.
Sources close to Rivlin said that although he prefers a unity government, Kulanu leader Moshe Kahlon would play a key role n deciding who forms a coalition, and that if Kahlon joins Netanyahu, a right-wing government may be a done deal.
Kahlon intends to wait for final results before he decides his party's preference.
Netanyahu's campaign adviser Nir Hefetz said the prime minister would keep his promise to form a right-wing government. But other Netanyahu associates said if the right-bloc does not end up winning 65 seats, inviting a Center-Left party would still be considered to expand the coalition after all the Likud's satellite parties joined.
Sources close to Netanyahu revealed that in the party's internal polls, Likud was down by four seats Thursday night and closed the gap to a tie by Sunday thanks to a series of interviews by Netanyahu in which he warned right-wing voters of a potential Herzog-led government.
"Pressuring right-wing voters was the right thing to do in retrospect," a Netanyahu associate said. "With what we were up against - with all the funding and support the Left was receiving from abroad - it's an absolute miracle that we won."
Likud strategist Aron Shaviv advised Netanyahu from the start of the campaign to push what he called "reverse packaging." The strategy was to persuade voters on the Right that rather than vote for other right-wing parties and get Netanyahu, they had to vote for Netanyahu and get the other parties in the coalition.
"You vote for a prime minister and get the parts," a Netanyahu associate said. "You don't buy a radio and get a car with it. You buy a car and get a radio. You vote Netanyahu and get Bennett and Kahlon with it."