Voting has closed in Israel's general election and exit polls are suggesting a virtual dead-heat.
Two leading television channels say the governing Likud party and the Zionist Union have won 27 seats each in the 120 member parliament, while a third channel says Likud has won 28 seats to 27.
Whichever side gets the most seats, commentators said forming a government will be a serious challenge for either of them. A clear indication of the result is not expected until later today.
A new centrist party, Kulanu, led by a former member of Mr Netanyahu's right-wing Likud, seemed destined to emerge the kingmaker in possibly weeks of coalition negotiations.
The election had turned into a referendum on whether Israelis had grown tired of the leader they call "Bibi" after nine years in power spread over three terms.
Mr Netanyahu took extraordinary steps to drum up support from right-wing voters, reversing policy on the eve of the election with an announcement that he would never allow a Palestinian state.
On election day he accused left-wing groups of trying to remove him from power by busing Arab Israeli voters to polling stations, a statement that drew a sharp rebuke from Washington.
If the exit polls prove accurate, Mr Netanyahu could have smoother path towards a coalition, with right-wing and religious parties his traditional allies.
But Yitzhak Herzog leader of Zionist Union also could prevail, should Kulanu and a bloc of Arab Israelis - which the polls predicted would be Israel's third largest party - throw their support behind him.
A national unity government grouping both major parties is also possible. Before the vote, Mr Netanyahu rejected such a coalition.
A fourth Netanyahu term would probably also prolong his prickly relationship with Israel's main ally, the United States, at least as long as Barack Obama is in the White House.
Mr Netanyahu has focused on the threat from Iran's nuclear programme and militant Islam. But many Israelis say they are tiring of the message, and the centre-left's campaign on social and economic issues, especially the high cost of housing and everyday living in Israel, appears to have won support.
No party has ever won an outright majority in Israel's 67-year history. It is up to Israel's president, after consulting with parties that won seats in parliament, to choose a leader to try to form a coalition.
The nominee will have up to 42 days to negotiate a coalition, and it may be mid-May at the earliest before Israel has a new government.
- Reuters, BBC