Unofficial results in Israel's second election in five months suggest it is too close to call, Israeli media say.
Incumbent PM Benjamin Netanyahu's party and that of his main challenger, Benny Gantz, are neck and neck with 32 seats each, the Kan public broadcaster says.
A prime minister needs to command a 61-seat majority in parliament. The smaller Yisrael Beiteinu party appears to hold the balance of power.
Official partial results are expected on Wednesday morning.
Benjamin Netanyahu, Israel's longest-serving leader, is vying to win a record fifth term in office.
Mr Netanyahu, who leads the right-wing Likud party, has pledged to annex Jewish settlements and a swathe of other territory in the occupied West Bank if he is returned to power.
Palestinians, who seek a state in the West Bank and Gaza, with its capital in occupied East Jerusalem, have warned such a move will kill any hopes for peace.
Mr Gantz, who leads the centrist Blue and White party, has not advocated any form of annexation though his position on the creation of a Palestinian state is unclear.
Like Mr Netanyahu, he has ruled out ever dividing Jerusalem, which Israel considers its capital.
On Wednesday morning, Yisrael Beiteinu's leader Avigdor Lieberman, reiterated that he would only support a government comprising both Likud and Blue and White.
However, Blue and White has ruled out sitting with Mr Netanyahu in a coalition.
What are the latest results?
Official results have been slow to be released, with only 30% of votes counted by 09:15 (06:15 GMT).
They put Likud slightly ahead of Blue and White, with the ultra-Orthodox Shas party third and Yisrael Beiteinu fourth, but without indicating how this translates into seats in the knesset (parliament).
According to the Times of Israel, Kan is reporting unofficial results based on what it says is 96.9% of votes counted.
It puts Likud and Blue and White both on 32 seats; the Israeli Arab Joint List second on 12 seats; Yisrael Beiteinu on nine; the ultra-Orthodox parties on 17 between them; the right-wing Yamina alliance on seven; Labour-Gesher on 6 and the centre-left Democratic Camp on 5.
Based on these reported results, neither Mr Netanyahu nor Mr Gantz can form a majority coalition without support from Yisrael Beiteinu.
Exit polls earlier presented a similar picture.
There was a muted response at Likud's election night headquarters in Tel Aviv.
Hundreds of chairs for party supporters remained empty, as activists were kept outside the hall and leaders digested the numbers.
Likud's foreign affairs director noted that Israeli exit polls had got things wrong in the past. Last time, they underestimated the number of votes for Likud and also for some of the religious parties allied to Mr Netanyahu.
"There is no point starting to work out a coalition based on these numbers as they will change," Eli Hazan said.
But Blue and White was "cautiously optimistic" that Israel would get new leadership, spokeswoman Melody Sucharewicz told the Times of Israel.
